Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Income Tax - Additional Information [Abstract]
Effective tax rate	9.20%	14.60%
Overall increase (decrease) in unrecognized tax benefits (UTPs)	$ 20.2
Excess Tax Benefit from Share Based Compensation	26.6
Reductions to Tax Positions	37.3
Net of Federal Tax [Member]
Income Tax - Additional Information [Abstract]
Overall increase (decrease) in unrecognized tax benefits (UTPs)	$ 20.2

No definition available.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to excess tax benefit for share-based compensation cost.

+ References

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Amount of increase (decrease) to previously recorded tax expense. Includes, but is not limited to, significant settlements of income tax disputes, and unusual tax positions or infrequent actions taken by the entity, including tax assessment reversal, and IRS tax settlement.

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Amount of increase (decrease) in unrecognized tax benefits attributable to uncertain tax positions taken in tax returns.

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