Consolidated Statement of Changes in Shareholders' Equity (Unaudited) shares in Millions, $ in Millions	USD ($) shares
Balance, beginning of year at Dec. 31, 2013	$ 21,500
Common stock
Employee share-based compensation	120
Compensation amortization under share-based plans and other changes	144
Balance, end of period at Sep. 30, 2014	21,764
Balance, beginning of year at Dec. 31, 2013	24,291
Retained earnings
Net income	2,654
Dividends	(553)
Other	2
Balance, end of period at Sep. 30, 2014	26,394
Balance, beginning of year at Dec. 31, 2013	810
Accumulated other comprehensive income, net of tax
Other comprehensive income (loss)	490
Balance, end of period at Sep. 30, 2014	1,300
Balance, beginning of year at Dec. 31, 2013	(21,805)
Treasury stock (at cost)
Treasury stock acquired - share repurchase authorization	(2,275)
Net shares acquired related to employee share-based compensation plans	(57)
Balance, end of period at Sep. 30, 2014	$ (24,137)
Balance, beginning of year at Dec. 31, 2013 | shares	353.5
Common shares outstanding
Treasury stock acquired - share repurchase authorization | shares	(25.4)
Net shares issued under employee share-based compensation plans | shares	3.3
Balance, end of period at Sep. 30, 2014 | shares	331.4
Treasury stock (at cost)
Total shareholders' equity	$ 25,321
Total shareholders' equity	24,836
Balance, beginning of year at Dec. 31, 2014	21,843
Common stock
Employee share-based compensation	105
Compensation amortization under share-based plans and other changes	151
Balance, end of period at Sep. 30, 2015	22,099
Balance, beginning of year at Dec. 31, 2014	27,251
Retained earnings
Net income	2,573
Dividends	(561)
Balance, end of period at Sep. 30, 2015	29,263
Balance, beginning of year at Dec. 31, 2014	880
Accumulated other comprehensive income, net of tax
Other comprehensive income (loss)	(848)
Balance, end of period at Sep. 30, 2015	32
Balance, beginning of year at Dec. 31, 2014	(25,138)
Treasury stock (at cost)
Treasury stock acquired - share repurchase authorization	(2,150)
Net shares acquired related to employee share-based compensation plans	(73)
Balance, end of period at Sep. 30, 2015	$ (27,361)
Balance, beginning of year at Dec. 31, 2014 | shares	322.2
Common shares outstanding
Treasury stock acquired - share repurchase authorization | shares	(20.8)
Net shares issued under employee share-based compensation plans | shares	2.8
Balance, end of period at Sep. 30, 2015 | shares	304.2
Treasury stock (at cost)
Total shareholders' equity	$ 24,033