Supplemental Equity and Comprehensive Income Information - SE Rf (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Increase (decrease) in equity
Balance at the beginning of the period	$ 10,142	$ 10,428	$ 9,848	$ 11,622
Net income	1,588	1,546	3,612	4,014
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	(202)	(112)	(2)	(441)
Defined benefit pension and postretirement plans adjustment	76	114	356	344
Cash flow hedging instruments	8	46	(24)	147
Total other comprehensive income (loss), net of tax	(118)	48	330	50
Dividends declared	(828)	(794)	(2,488)	(2,406)
Stock-based compensation	49	47	218	245
Reacquired stock	(141)	(1,058)	(1,211)	(3,621)
Issuances pursuant to stock option and benefit plans	72	94	441	407
Balance at the end of the period	10,764	10,311	10,764	10,311
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	5,821	5,559	5,652	5,361
Other comprehensive income (loss), net of tax:
Stock-based compensation	49	47	218	245
Balance at the end of the period	5,870	5,606	5,870	5,606
Retained Earnings
Increase (decrease) in equity
Balance at the beginning of the period	41,362	39,442	40,636	39,115
Net income	1,583	1,543	3,601	4,002
Other comprehensive income (loss), net of tax:
Dividends declared	(828)	(794)	(2,488)	(2,406)
Issuances pursuant to stock option and benefit plans	(32)	(71)	(531)	(591)
Balance at the end of the period	42,085	40,120	42,085	40,120
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	(29,828)	(27,617)	(29,626)	(25,887)
Other comprehensive income (loss), net of tax:
Reacquired stock	(141)	(1,058)	(1,211)	(3,621)
Issuances pursuant to stock option and benefit plans	104	165	972	998
Balance at the end of the period	(29,865)	(28,510)	(29,865)	(28,510)
Total Accumulated Other Comprehensive Income (Loss)
Increase (decrease) in equity
Balance at the beginning of the period	(7,272)	(7,019)	(6,866)	(7,026)
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	(200)	(109)	(1)	(433)
Defined benefit pension and postretirement plans adjustment	76	114	356	344
Cash flow hedging instruments	8	46	(24)	147
Balance at the end of the period	(7,388)	(6,968)	(7,388)	(6,968)
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	59	63	52	59
Net income	5	3	11	12
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	(2)	(3)	(1)	(8)
Balance at the end of the period	$ 62	$ 63	$ 62	$ 63