Supplemental Equity and Comprehensive Income Information - SE Rf (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Increase (decrease) in equity
Balance at the beginning of the period	$ 10,915	$ 10,142	$ 10,126	$ 9,848
Net income	1,417	1,588	3,998	3,612
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	271	(202)	(67)	(2)
Defined benefit pension and postretirement plans adjustment	127	76	304	356
Cash flow hedging instruments	(71)	8	(60)	(24)
Total other comprehensive income (loss), net of tax	327	(118)	177	330
Dividends declared	(847)	(828)	(2,540)	(2,488)
Purchase of subsidiary shares			(1)
Stock-based compensation	42	49	209	218
Reacquired stock	(1)	(141)	(357)	(1,211)
Issuances pursuant to stock option and benefit plans	90	72	331	441
Balance at the end of the period	11,943	10,764	11,943	10,764
ASU 2016-02 Leases | Cumulative Effect, Period of Adoption, Adjustment
Increase (decrease) in equity
Balance at the beginning of the period				14
Common Stock and Additional Paid-in Capital
Increase (decrease) in equity
Balance at the beginning of the period	6,083	5,821	5,916	5,652
Other comprehensive income (loss), net of tax:
Stock-based compensation	42	49	209	218
Balance at the end of the period	6,125	5,870	6,125	5,870
Retained Earnings
Increase (decrease) in equity
Balance at the beginning of the period	42,759	41,362	42,135	40,636
Net income	1,413	1,583	3,995	3,601
Other comprehensive income (loss), net of tax:
Dividends declared	(847)	(828)	(2,540)	(2,488)
Issuances pursuant to stock option and benefit plans	(40)	(32)	(305)	(531)
Balance at the end of the period	43,285	42,085	43,285	42,085
Retained Earnings | ASU 2018-02 Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income | Cumulative Effect, Period of Adoption, Adjustment
Increase (decrease) in equity
Balance at the beginning of the period				853
Retained Earnings | ASU 2016-02 Leases | Cumulative Effect, Period of Adoption, Adjustment
Increase (decrease) in equity
Balance at the beginning of the period				14
Treasury Stock
Increase (decrease) in equity
Balance at the beginning of the period	(29,699)	(29,828)	(29,849)	(29,626)
Other comprehensive income (loss), net of tax:
Reacquired stock	(1)	(141)	(357)	(1,211)
Issuances pursuant to stock option and benefit plans	130	104	636	972
Balance at the end of the period	(29,570)	(29,865)	(29,570)	(29,865)
Total Accumulated Other Comprehensive Income (Loss)
Increase (decrease) in equity
Balance at the beginning of the period	(8,286)	(7,272)	(8,139)	(6,866)
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	270	(200)	(65)	(1)
Defined benefit pension and postretirement plans adjustment	127	76	304	356
Cash flow hedging instruments	(71)	8	(60)	(24)
Balance at the end of the period	(7,960)	(7,388)	(7,960)	(7,388)
Total Accumulated Other Comprehensive Income (Loss) | ASU 2018-02 Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income | Cumulative Effect, Period of Adoption, Adjustment
Increase (decrease) in equity
Balance at the beginning of the period				(853)
Other comprehensive income (loss), net of tax:
Balance at the end of the period		(853)		(853)
Noncontrolling Interest
Increase (decrease) in equity
Balance at the beginning of the period	58	59	63	52
Net income	4	5	3	11
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	1	(2)	(2)	(1)
Purchase of subsidiary shares			(1)
Balance at the end of the period	$ 63	$ 62	$ 63	$ 62