Income Taxes - Income Tax Expense and Income Before Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
Current income taxes (benefits): U.S. federal	$ 31.9	$ (48.9)	$ (4.4)
Current income taxes (benefits): State	18.1	10.3	48.9
Current income taxes (benefits): Foreign	45.6	51.7	38.1
Current income taxes (benefits): Tax benefit of operating loss carryforwards	(3.0)	(13.5)	(21.5)
Total current income taxes (benefits)	92.6	(0.4)	61.1
Deferred income taxes (benefits): U.S. federal	108.6	224.3	(208.2)
Deferred income taxes (benefits): State	6.9	19.2	42.5
Deferred income taxes (benefits): Foreign	41.1	(12.4)	32.3
Total deferred income taxes (benefits)	156.6	231.1	(133.4)
Income taxes (benefits)	249.2	230.7	(72.3)
Income (loss) before income taxes
Income (loss) before income taxes - domestic	1,365.1	1,658.1	1,848.5
Income (loss) before income taxes - foreign	328.2	126.3	403.7
Income (loss) before income taxes	$ 1,693.3	$ 1,784.4	$ 2,252.2