Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other net periodic benefit costs	$ (3)	$ 14	$ 19
Foreign currency translation adjustment related to sale of U.K. business	(30)	0	0
Income taxes related to sale of U.K. business (b)	(7)	0	(4)
Net gain on disposal of assets	50	319	58
Net interest and other	(244)	(226)	(270)
Net income (loss)	480	1,096	$ (5,723)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other net periodic benefit costs	(6)	14
U.K. pension plan transferred to buyer	83	0
Foreign currency translation adjustment related to sale of U.K. business	(30)	0
Net gain on disposal of assets	68	0
Net interest and other	1	0
Net income (loss)	75	(14)
Amortization of prior service credit | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other net periodic benefit costs	(26)	(18)
Amortization of actuarial loss | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other net periodic benefit costs	8	12
Net settlement loss, net of tax | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other net periodic benefit costs	12	21
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax	(12)	(20)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income taxes related to sale of U.K. business (b)	$ (45)	$ 0