Supplementary Information (Schedule of Foreign Exchange Gain (Loss)) (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended	8 Months Ended	9 Months Ended
	Sep. 30, 2017	Aug. 31, 2017	Sep. 30, 2016	Aug. 31, 2017	Sep. 30, 2016
Successor
Foreign Currency Exchange Gain (Loss) [Line Items]
Net exchange (losses) gains	$ 77
Net exchange (losses) gains, tax	(71)
Net exchange (losses) gains, after-tax	6
Successor | Subsidiary Monetary Position Gain (Loss) [Member]
Foreign Currency Exchange Gain (Loss) [Line Items]
Net exchange (losses) gains	(35)
Net exchange (losses) gains, tax	(31)
Net exchange (losses) gains, after-tax	(66)
Successor | Hedging Program Gain (Loss) [Member]
Foreign Currency Exchange Gain (Loss) [Line Items]
Net exchange (losses) gains	112
Net exchange (losses) gains, tax	(40)
Net exchange (losses) gains, after-tax	$ 72
Predecessor
Foreign Currency Exchange Gain (Loss) [Line Items]
Net exchange (losses) gains		$ (195)	$ (76)	$ (394)	$ (212)
Net exchange (losses) gains, tax		182	48	372	114
Net exchange (losses) gains, after-tax		(13)	(28)	(22)	(98)
Predecessor | Subsidiary Monetary Position Gain (Loss) [Member]
Foreign Currency Exchange Gain (Loss) [Line Items]
Net exchange (losses) gains		65	6	37	185
Net exchange (losses) gains, tax		88	18	217	(29)
Net exchange (losses) gains, after-tax		153	24	254	156
Predecessor | Hedging Program Gain (Loss) [Member]
Foreign Currency Exchange Gain (Loss) [Line Items]
Net exchange (losses) gains		(260)	(82)	(431)	(397)
Net exchange (losses) gains, tax		94	30	155	143
Net exchange (losses) gains, after-tax		$ (166)	$ (52)	$ (276)	$ (254)