Consolidated Statement of Changes in Equity (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Increase (decrease) in equity
Balance at the beginning of the period	$ 10,343	$ 11,468
Net income	1,326	1,278
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	292	138
Defined benefit pension and postretirement plans adjustment	83	69
Cash flow hedging instruments - unrealized gain (loss)	(76)	(110)
Total other comprehensive income (loss), net of tax	299	97
Dividends declared	(702)	(672)
Stock-based compensation	128	125
Reacquired stock	(678)	(1,163)
Issuances pursuant to stock option and benefit plans	324	362
Balance at the end of the period	11,040	11,495
Common Stock and Additional Paid-in Capital
Increase (decrease) in equity
Balance at the beginning of the period	5,070	4,800
Other comprehensive income (loss), net of tax:
Stock-based compensation	128	125
Balance at the end of the period	5,198	4,925
Retained Earnings
Increase (decrease) in equity
Balance at the beginning of the period	37,907	36,296
Net income	1,323	1,275
Other comprehensive income (loss), net of tax:
Dividends declared	(702)	(672)
Issuances pursuant to stock option and benefit plans	(434)	(393)
Balance at the end of the period	38,094	36,506
Treasury Stock
Increase (decrease) in equity
Balance at the beginning of the period	(25,434)	(23,308)
Other comprehensive income (loss), net of tax:
Reacquired stock	(678)	(1,163)
Issuances pursuant to stock option and benefit plans	758	755
Balance at the end of the period	(25,354)	(23,716)
Accumulated Other Comprehensive Income (Loss)
Increase (decrease) in equity
Balance at the beginning of the period	(7,245)	(6,359)
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	289	139
Defined benefit pension and postretirement plans adjustment	83	69
Cash flow hedging instruments - unrealized gain (loss)	(76)	(110)
Balance at the end of the period	(6,949)	(6,261)
Noncontrolling Interest
Increase (decrease) in equity
Balance at the beginning of the period	45	39
Net income	3	3
Other comprehensive income (loss), net of tax:
Cumulative translation adjustment	3	(1)
Balance at the end of the period	$ 51	$ 41