Supplemental Equity and Comprehensive Income Information - SE Rf (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Increase (decrease) in equity
Balance at the beginning of the period	$ 12,931	$ 10,126
Net income	1,627	1,310
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	(222)	(444)
Defined benefit pension and postretirement plans adjustment	119	108
Cash flow hedging instruments	58	47
Total other comprehensive income (loss), net of tax	(45)	(289)
Dividends declared	(858)	(847)
Stock-based compensation	121	117
Reacquired stock	(243)	(356)
Issuances pursuant to stock option and benefit plans	295	153
Balance at the end of the period	13,828	10,214
Common Stock and Additional Paid-in Capital
Increase (decrease) in equity
Balance at the beginning of the period	6,171	5,916
Other comprehensive income (loss), net of tax:
Stock-based compensation	121	117
Balance at the end of the period	6,292	6,033
Retained Earnings
Increase (decrease) in equity
Balance at the beginning of the period	43,821	42,130
Net income	1,624	1,308
Other comprehensive income (loss), net of tax:
Dividends declared	(858)	(847)
Issuances pursuant to stock option and benefit plans	(332)	(235)
Balance at the end of the period	44,255	42,356
Treasury Stock
Increase (decrease) in equity
Balance at the beginning of the period	(29,404)	(29,849)
Other comprehensive income (loss), net of tax:
Reacquired stock	(243)	(356)
Issuances pursuant to stock option and benefit plans	627	388
Balance at the end of the period	(29,020)	(29,817)
Total Accumulated Other Comprehensive Income (Loss)
Increase (decrease) in equity
Balance at the beginning of the period	(7,721)	(8,134)
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	(223)	(441)
Defined benefit pension and postretirement plans adjustment	119	108
Cash flow hedging instruments	58	47
Balance at the end of the period	(7,767)	(8,420)
Noncontrolling Interest
Increase (decrease) in equity
Balance at the beginning of the period	64	63
Net income	3	2
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	1	(3)
Balance at the end of the period	$ 68	$ 62