Supplemental Equity and Comprehensive Income Information - SE Rf (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Increase (decrease) in equity
Balance at the beginning of the period	$ 11,039	$ 11,040	$ 11,622	$ 10,343
Net income	1,862	1,585	2,468	2,911
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	(496)	(67)	(329)	225
Defined benefit pension and postretirement plans adjustment	114	78	230	161
Cash flow hedging instruments unrealized gain (loss)	162	(51)	101	(127)
Total other comprehensive income (loss), net of tax	(220)	(40)	2	259
Dividends declared	(802)	(701)	(1,612)	(1,403)
Stock-based compensation	54	55	(198)	183
Reacquired stock	(1,591)	(475)	(2,563)	(1,153)
Issuances pursuant to stock option and benefit plans	86	180	313	504
Balance at the end of the period	10,428	11,644	10,428	11,644
Common Stock and Additional Paid-in Capital
Increase (decrease) in equity
Balance at the beginning of the period	5,505	5,198	5,361	5,070
Other comprehensive income (loss), net of tax:
Stock-based compensation	54	55	(198)	183
Balance at the end of the period	5,559	5,253	5,559	5,253
Retained Earnings
Increase (decrease) in equity
Balance at the beginning of the period	38,453	38,094	39,115	37,907
Net income	1,857	1,583	2,459	2,906
Other comprehensive income (loss), net of tax:
Dividends declared	(802)	(701)	(1,612)	(1,403)
Issuances pursuant to stock option and benefit plans	(66)	(183)	(520)	(617)
Balance at the end of the period	39,442	38,793	39,442	38,793
Treasury Stock
Increase (decrease) in equity
Balance at the beginning of the period	(26,178)	(25,354)	(25,887)	(25,434)
Other comprehensive income (loss), net of tax:
Reacquired stock	(1,591)	(475)	(2,563)	(1,153)
Issuances pursuant to stock option and benefit plans	152	363	833	1,121
Balance at the end of the period	(27,617)	(25,466)	(27,617)	(25,466)
Accumulated Other Comprehensive Income (Loss)
Increase (decrease) in equity
Balance at the beginning of the period	(6,803)	(6,949)	(7,026)	(7,245)
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	(492)	(67)	(324)	222
Defined benefit pension and postretirement plans adjustment	114	78	230	161
Cash flow hedging instruments unrealized gain (loss)	162	(51)	101	(127)
Balance at the end of the period	(7,019)	(6,989)	(7,019)	(6,989)
Noncontrolling Interest
Increase (decrease) in equity
Balance at the beginning of the period	62	51	59	45
Net income	5	2	9	5
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	(4)		(5)	3
Balance at the end of the period	$ 63	$ 53	$ 63	$ 53