Income Taxes - Schedule of Provision for Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Federal	$ 121.4	$ 272.1	$ 126.6
State	31.0	21.4	39.0
Foreign	203.5	168.5	87.0
Total current	355.9	462.0	252.6
Deferred	(1,597.9)	(1,781.8)	33.4
Total income tax provision (benefit)	(1,242.0)	(1,319.8)	286.0
Total provision - discontinued operations	236.1	258.6	228.9
Total provision (benefit)- continuing operations	$ (1,478.1)	$ (1,578.4)	$ 57.1

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

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Amount of current state and local tax expense (benefit) pertaining to income (loss) from continuing operations.

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