Components of Accumulated Other Comprehensive Loss, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ (1,945)
Other comprehensive (loss) income, unrecognized amounts on retirement benefits	(59)	$ 25	$ 64
Other comprehensive (loss) income, foreign currency translation adjustment	327	(494)	546
Other comprehensive (loss) income, unrealized gains on available-for-sale securities	0	0	500
Other comprehensive (loss) income, unrealized gains on cash flow hedges	(29)	7	3
Other Comprehensive Income (Loss), Net of Tax	239	(462)	1,113
Ending balance	(1,706)	(1,945)
Accumulated Other Comprehensive Loss, Net [Member]
Accumulated Other Comprehensive Loss, Net [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		(1,085)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance, unrecognized amounts on retirement benefits	(358)	(383)	(447)
Balance, foreign currency translation adjustment	(1,623)	(1,129)	(1,675)
Beginning balance	0	1,085	585
Beginning balance	36	29	26
Beginning balance	(1,945)	(398)	(1,511)
Other comprehensive (loss) income, unrecognized amounts on retirement benefits	(59)	25	64
Other comprehensive (loss) income, foreign currency translation adjustment	327	(494)	546
Other comprehensive (loss) income, unrealized gains on available-for-sale securities	0	0	500
Other comprehensive (loss) income, unrealized gains on cash flow hedges	(29)	7	3
Other Comprehensive Income (Loss), Net of Tax	239	(462)	1,113
Balance, unrecognized amounts on retirement benefits	(417)	(358)	(383)
Balance, foreign currency translation adjustment	(1,296)	(1,623)	(1,129)
Ending balance	0	0	1,085
Ending balance	7	36	29
Ending balance	$ (1,706)	$ (1,945)	$ (398)