Debt - Components of Debt (Details) € in Millions			12 Months Ended
Debt - Components of Debt (Details) € in Millions	Sep. 21, 2020 USD ($)	Jan. 22, 2020 EUR (€)	Dec. 31, 2021 EUR (€) extension	Dec. 31, 2021 USD ($)	Dec. 31, 2021 EUR (€)	Dec. 31, 2020 USD ($)	Mar. 31, 2020 USD ($)
Debt Instrument [Line Items]
Deferred financing costs				$ (27,800,000)		$ (29,500,000)
Total				$ 3,492,900,000		3,409,000,000
LIBOR \| USD
Debt Instrument [Line Items]
Interest rate				0.11%	0.11%
Term Loan \| LIBOR \| 2023 Term Loan Facility
Debt Instrument [Line Items]
Basis spread on variable rate			1.20%
Term Loan \| LIBOR \| 2025 Term Loan Facility
Debt Instrument [Line Items]
Basis spread on variable rate			1.20%
Senior Notes \| 2024 Notes, including bond discount of $0.6 million and $0.7 million, respectively
Debt Instrument [Line Items]
Long-term debt, gross						599,300,000
Interest rate				2.90%	2.90%
Bond discount (premium)				$ 600,000		700,000
Senior Notes \| 2024 Notes, including bond discount of $0.6 million and $0.7 million, respectively \| Carrying Value
Debt Instrument [Line Items]
Long-term debt, gross				$ 599,400,000		599,300,000
Senior Notes \| 2027 Notes, including bond discount of $0.6 million and $0.6 million, respectively(d)
Debt Instrument [Line Items]
Long-term debt, gross						612,600,000
Interest rate		1.45%		1.45%	1.45%
Bond discount (premium)				$ 600,000	€ 0.7	600,000
Proceeds from debt \| €		€ 495.3	€ 495.3
Senior Notes \| 2027 Notes, including bond discount of $0.6 million and $0.6 million, respectively(d) \| Carrying Value
Debt Instrument [Line Items]
Long-term debt, gross				$ 566,600,000		612,600,000
Senior Notes \| 2028 Notes, including bond discount of $6.9 million
Debt Instrument [Line Items]
Long-term debt, gross						0
Interest rate				1.125%	1.125%
Bond discount (premium)				$ 6,900,000	€ 6.7
Proceeds from debt \| €			€ 489.2
Senior Notes \| 2028 Notes, including bond discount of $6.9 million \| Carrying Value
Debt Instrument [Line Items]
Long-term debt, gross				$ 560,300,000		0
Senior Notes \| 2029 Notes, including bond discount of $1.4 million and $1.6 million, respectively
Debt Instrument [Line Items]
Long-term debt, gross						598,400,000
Interest rate				3.45%	3.45%
Bond discount (premium)				$ 1,400,000		1,600,000
Senior Notes \| 2029 Notes, including bond discount of $1.4 million and $1.6 million, respectively \| Carrying Value
Debt Instrument [Line Items]
Long-term debt, gross				$ 598,600,000		598,400,000
Senior Notes \| 2030 Notes, including bond discount of $4.2 million and $4.7 million, respectively
Debt Instrument [Line Items]
Interest rate	2.15%			2.15%	2.15%
Bond discount (premium)				$ 4,200,000		4,700,000
Proceeds from debt	$ 392,600,000
Senior Notes \| 2030 Notes, including bond discount of $4.2 million and $4.7 million, respectively \| Carrying Value
Debt Instrument [Line Items]
Long-term debt, gross				395,800,000		395,300,000
Revolving Credit Facility
Debt Instrument [Line Items]
Option to extend maturity of debt, period			1 year
Revolving Credit Facility \| Fair Value
Debt Instrument [Line Items]
Long-term debt, gross				0		432,900,000
Revolving Credit Facility \| Carrying Value
Debt Instrument [Line Items]
Long-term debt, gross				0		432,900,000
Revolving Credit Facility \| 1.4 Billion Senior Multi Currency Revolving Credit Facility
Debt Instrument [Line Items]
Borrowings on line of credit				0
Option to extend maturity of debt, period			12 months
Number of extension options \| extension			1
Revolving Credit Facility \| $3 Billion Credit Facility
Debt Instrument [Line Items]
Borrowings on line of credit							$ 1,300,000,000
Revolving Credit Facility \| EUR Revolver
Debt Instrument [Line Items]
Borrowings on line of credit				0		275,900,000
Revolving Credit Facility \| GBP Revolver
Debt Instrument [Line Items]
Borrowings on line of credit				0		157,000,000.0
Revolving Credit Facility \| 2023 Term Loan Facility
Debt Instrument [Line Items]
Option to extend maturity of debt, period			1 year
Number of extension options \| extension			2
Revolving Credit Facility \| 2023 Term Loan Facility \| Fair Value
Debt Instrument [Line Items]
Borrowings on line of credit				100,000,000.0		100,000,000.0
Revolving Credit Facility \| 2023 Term Loan Facility \| Carrying Value
Debt Instrument [Line Items]
Borrowings on line of credit				100,000,000.0		100,000,000.0
Revolving Credit Facility \| 2025 Term Loan Facility \| Fair Value
Debt Instrument [Line Items]
Borrowings on line of credit				700,000,000.0		700,000,000.0
Revolving Credit Facility \| 2025 Term Loan Facility \| Carrying Value
Debt Instrument [Line Items]
Borrowings on line of credit				$ 700,000,000.0		$ 700,000,000.0
Revolving Credit Facility \| EURIBOR \| 1.4 Billion EUR Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate			1.00%
Revolving Credit Facility \| GPB LIBOR \| 1.4 Billion GBP Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate			1.00%

CyrusOne Inc. 10-K