Lease Disclosures - Components of Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Finance lease cost:
Amortization of right-of-use assets	$ 1.1	$ 1.1	$ 2.2	$ 2.3
Interest on lease liabilities	1.2	1.4	2.5	2.8
Operating lease cost	21.2	21.0	42.3	42.4
Variable lease cost	1.9	0.5	3.6	0.7
Short-term lease cost	0.0	0.0	0.0	0.0
Sublease income	(26.6)	(24.9)	(53.1)	(49.1)
Lease (income) cost	$ (1.2)	(0.9)	$ (2.5)	(0.9)
Previously Reported
Finance lease cost:
Operating lease cost		$ 24.7		$ 49.8