Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Employee benefit plan expenses	$ 35	$ 34	$ 25

Amount of cost (reversal of cost) for pension and other postretirement benefits.

No definition available.

Name:	us-gaap_PensionAndOtherPostretirementBenefitExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration