Supplemental Equity and Comprehensive Income Information - SE Rf (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Increase (decrease) in equity
Balance at the beginning of the period	$ 9,757	$ 11,039	$ 9,848	$ 11,622
Net income	1,131	1,862	2,024	2,468
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	123	(496)	200	(329)
Defined benefit pension and postretirement plans adjustment	196	114	280	230
Cash flow hedging instruments	(38)	162	(32)	101
Total other comprehensive income (loss), net of tax	281	(220)	448	2
Dividends declared	(830)	(802)	(1,660)	(1,612)
Stock-based compensation	57	54	169	198
Reacquired stock	(404)	(1,591)	(1,070)	(2,563)
Issuances pursuant to stock option and benefit plans	150	86	369	313
Balance at the end of the period	10,142	10,428	10,142	10,428
ASU 2016-02 Leases
Increase (decrease) in equity
Impact of ASUs	14		14
Common Stock and Additional Paid-in Capital
Increase (decrease) in equity
Balance at the beginning of the period	5,764	5,505	5,652	5,361
Other comprehensive income (loss), net of tax:
Stock-based compensation	57	54	169	198
Balance at the end of the period	5,821	5,559	5,821	5,559
Retained Earnings
Increase (decrease) in equity
Balance at the beginning of the period	41,159	38,453	40,636	39,115
Net income	1,127	1,857	2,018	2,459
Other comprehensive income (loss), net of tax:
Dividends declared	(830)	(802)	(1,660)	(1,612)
Issuances pursuant to stock option and benefit plans	(94)	(66)	(499)	(520)
Balance at the end of the period	41,362	39,442	41,362	39,442
Retained Earnings | ASU 2018-02 Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income
Increase (decrease) in equity
Impact of ASUs	853		853
Retained Earnings | ASU 2016-02 Leases
Increase (decrease) in equity
Impact of ASUs	14		14
Treasury Stock
Increase (decrease) in equity
Balance at the beginning of the period	(29,668)	(26,178)	(29,626)	(25,887)
Other comprehensive income (loss), net of tax:
Reacquired stock	(404)	(1,591)	(1,070)	(2,563)
Issuances pursuant to stock option and benefit plans	244	152	868	833
Balance at the end of the period	(29,828)	(27,617)	(29,828)	(27,617)
Total Accumulated Other Comprehensive Income (Loss)
Increase (decrease) in equity
Balance at the beginning of the period	(7,552)	(6,803)	(6,866)	(7,026)
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	122	(492)	199	(324)
Defined benefit pension and postretirement plans adjustment	196	114	280	230
Cash flow hedging instruments	(38)	162	(32)	101
Balance at the end of the period	(7,272)	(7,019)	(7,272)	(7,019)
Total Accumulated Other Comprehensive Income (Loss) | ASU 2018-02 Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income
Increase (decrease) in equity
Impact of ASUs	(853)		(853)
Total Accumulated Other Comprehensive Income (Loss) | ASU 2016-02 Leases
Increase (decrease) in equity
Impact of ASUs	(853)		(853)
Noncontrolling Interest
Increase (decrease) in equity
Balance at the beginning of the period	54	62	52	59
Net income	4	5	6	9
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	1	(4)	1	(5)
Balance at the end of the period	$ 59	$ 63	$ 59	$ 63