CONSOLIDATED STATEMENTS OF CASH FLOWS CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) $ in Millions	1 Months Ended
Mar. 31, 2017 USD ($)
Statement of Cash Flows [Abstract]
Defined benefit plan contributions made	$ (135)

Amount of contribution received by defined benefit plan from employer which increases plan assets.

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