Fair Value of Assets and Liabilities - Summary of Liabilities Recorded at Carrying Value (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Senior Notes Due 2024 [Member]
Debt Instrument [Line Items]
Senior Notes	$ 400.0	$ 400.0
Senior Notes Fair Value	408.0	400.0
Senior Notes Due 2025 [Member]
Debt Instrument [Line Items]
Senior Notes	700.0	700.0
Senior Notes Fair Value	773.5	778.8
Senior Notes Due 2025 EURO [Member]
Debt Instrument [Line Items]
Senior Notes	415.9	429.5
Senior Notes Fair Value	$ 457.0	$ 466.0