Debt - Additional Information (Detail) $ in Billions	Dec. 31, 2016 USD ($)
Debt Disclosure [Abstract]
Total debt borrowed at fixed rate	$ 0.9
Total debt borrowed at floating rate	$ 2.9

The portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

No definition available.

Name:	us-gaap_LongtermDebtPercentageBearingVariableInterestAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant