Employee Retirement Plans and Postretirement Benefits - Level 3 Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Total gain or loss (realized/unrealized):
Prior year fair value of assets	$ 5,958.4	$ 5,542.1
Foreign exchange translation (loss)/gain	(20.5)	113.9
Fair value of plan assets at end of year	5,667.5	5,958.4
Significant unobservable inputs (Level 3)
Total gain or loss (realized/unrealized):
Prior year fair value of assets	856.3	830.2
Realized gain (loss)	0.9	2.1
Unrealized gain (loss) included in AOCI	(63.3)	11.0
Purchases, issuances, settlements	(32.8)	(12.7)
Foreign exchange translation (loss)/gain	(6.6)	25.7
Fair value of plan assets at end of year	$ 754.5	$ 856.3