Comprehensive Income and Shareholders' Equity (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		$ 3,515	$ 2,531	$ 2,858
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		27,586	25,413	21,540
Cumulative effect of accounting changes		4	30
Other comprehensive income (loss) before reclassifications		(238)
Amounts reclassified from accumulated other comprehensive items		57
Total other comprehensive items		(181)	(407)	633
Balance	$ 25,413	29,675	27,586	25,413
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		$ 3,515	2,531	2,858
Class of Stock Disclosures [Abstract]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)		25
Restatement Adjustment [Member] | Income Taxes on Net Investment Hedge [Member]
Stockholders' Equity Note [Abstract]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	101
Accumulated Other Comprehensive Income (Loss) [Line Items]
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	101
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		$ (2,243)
Other comprehensive income (loss) before reclassifications		(107)
Amounts reclassified from accumulated other comprehensive items		30
Total other comprehensive items		(77)
Balance		(2,320)	(2,243)
Unrealized Losses on Hedging Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		(52)
Other comprehensive income (loss) before reclassifications		(38)
Amounts reclassified from accumulated other comprehensive items		19
Total other comprehensive items		(19)
Balance		(71)	(52)
Pension and Other Postretirement Benefit Liability Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		(203)
Other comprehensive income (loss) before reclassifications		(93)
Amounts reclassified from accumulated other comprehensive items		8
Total other comprehensive items		(85)
Balance		(288)	(203)
Accumulated Other Comprehensive Items [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		(2,498)	(2,003)	(2,636)
Cumulative effect of accounting changes			(88)
Total other comprehensive items		(181)	(407)	633
Balance	$ (2,003)	$ (2,679)	$ (2,498)	$ (2,003)