Supplemental Equity and Comprehensive Income Information - SE Rf (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Increase (decrease) in equity
Balance at the beginning of the period	$ 11,644	$ 11,658	$ 10,343	$ 11,468
Net income	1,433	1,331	4,344	3,902
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	44	17	269	192
Defined benefit pension and postretirement plans adjustment	80	67	241	203
Cash flow hedging instruments - unrealized gain (loss)	(49)	(45)	(176)	(182)
Total other comprehensive income (loss), net of tax	75	39	334	213
Dividends declared	(701)	(670)	(2,104)	(2,014)
Stock-based compensation	58	49	241	221
Reacquired stock	(394)	(771)	(1,547)	(2,771)
Issuances pursuant to stock option and benefit plans	87	133	591	750
Balance at the end of the period	12,202	11,769	12,202	11,769
Common Stock and Additional Paid-in Capital
Increase (decrease) in equity
Balance at the beginning of the period	5,253	4,972	5,070	4,800
Other comprehensive income (loss), net of tax:
Stock-based compensation	58	49	241	221
Balance at the end of the period	5,311	5,021	5,311	5,021
Retained Earnings
Increase (decrease) in equity
Balance at the beginning of the period	38,793	36,915	37,907	36,296
Net income	1,429	1,329	4,335	3,895
Other comprehensive income (loss), net of tax:
Dividends declared	(701)	(670)	(2,104)	(2,014)
Issuances pursuant to stock option and benefit plans	(67)	(108)	(684)	(711)
Balance at the end of the period	39,454	37,466	39,454	37,466
Treasury Stock
Increase (decrease) in equity
Balance at the beginning of the period	(25,466)	(24,088)	(25,434)	(23,308)
Other comprehensive income (loss), net of tax:
Reacquired stock	(394)	(771)	(1,547)	(2,771)
Issuances pursuant to stock option and benefit plans	154	241	1,275	1,461
Balance at the end of the period	(25,706)	(24,618)	(25,706)	(24,618)
Accumulated Other Comprehensive Income (Loss)
Increase (decrease) in equity
Balance at the beginning of the period	(6,989)	(6,184)	(7,245)	(6,359)
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	45	16	267	192
Defined benefit pension and postretirement plans adjustment	80	67	241	203
Cash flow hedging instruments - unrealized gain (loss)	(49)	(45)	(176)	(182)
Balance at the end of the period	(6,913)	(6,146)	(6,913)	(6,146)
Noncontrolling Interest
Increase (decrease) in equity
Balance at the beginning of the period	53	43	45	39
Net income	4	2	9	7
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	(1)	1	2
Balance at the end of the period	$ 56	$ 46	$ 56	$ 46