Condensed Consolidated Statements of Changes in Stockholders' Equity Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stocks	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Stockholders' Equity, Total [Member]
Adjustments to Additional Paid in Capital [Abstract]
Additional Paid in Capital			$ 9,123
Retained Earnings (Accumulated Deficit) [Abstract]
Retained Earnings (Accumulated Deficit)				$ 11,191
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss), Net of Tax						$ 928
Adjustments to Additional Paid in Capital, Share-based Compensation, Employee Stock Purchase Program, Requisite Service Period Recognition			(153)
Allocated Share-based Compensation Expense			36
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation			26
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs			49
Net Income (Loss) Attributable to Parent	$ 880			880
Dividends, Common Stock, Cash				150
Treasury Stock, Value at Dec. 31, 2014					$ (2,527)
Treasury Stock Transactions, Excluding Value of Shares Reissued [Abstract]
Treasury stock acquired					(500)
Issuance of shares under incentive and stock compensation plans from treasury stock					(161)
Return of shares under incentive and stock compensation plans and other to treasury stock	(18)				(53)
Adjustments to Additional Paid in Capital, Stock Issued, Own-share Lending Arrangement, Issuance Costs					49
Treasury Stock, Value at Jun. 30, 2015					(2,870)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Income (Loss), Net of Tax	(740)					(740)
Common Shares Outstanding, at beginning of period (in thousands) at Dec. 31, 2014		424,416.0
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Treasury stock acquired		(12,117.0)
Issuance of shares under incentive and stock compensation plans		4,089.0
Return of shares under incentive and stock compensation plans and other to treasury stock		(1,299.0)
Issuance of Shares for Warrant Exercise		1,256.0
Common Shares Outstanding, at end of period (in thousands) at Jun. 30, 2015		416,345.0
Adjustments to Additional Paid in Capital [Abstract]
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation			0
Treasury Stock, Value at Dec. 31, 2014					(2,527)
Treasury Stock, Value at Dec. 31, 2015	(3,557)				(3,557)
Common Shares Outstanding, at beginning of period (in thousands) at Dec. 31, 2014		424,416.0
Common Shares Outstanding, at end of period (in thousands) at Dec. 31, 2015		401,821.0
Preferred Stock, Including Additional Paid in Capital [Abstract]
Common Stock, Value, Issued		$ 5
Adjustments to Additional Paid in Capital [Abstract]
Additional Paid in Capital			8,983
Retained Earnings (Accumulated Deficit) [Abstract]
Retained Earnings (Accumulated Deficit)				11,921
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss), Net of Tax						188
Total stockholders' equity							$ 18,227
Common Stock, Value, Issued	5
Additional Paid in Capital	8,973		8,973
Retained Earnings (Accumulated Deficit)	12,550			12,550
Accumulated Other Comprehensive Income (Loss), Net of Tax	(329)					(329)
Total stockholders' equity	17,642
Adjustments to Additional Paid in Capital, Share-based Compensation, Employee Stock Purchase Program, Requisite Service Period Recognition			(129)
Allocated Share-based Compensation Expense			39
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation			22
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs			8
Net Income (Loss) Attributable to Parent	539			539
Dividends, Common Stock, Cash				166
Treasury stock acquired					(700)
Issuance of shares under incentive and stock compensation plans from treasury stock					(130)
Return of shares under incentive and stock compensation plans and other to treasury stock	(10)				(47)
Adjustments to Additional Paid in Capital, Stock Issued, Own-share Lending Arrangement, Issuance Costs					8
Treasury Stock, Value at Jun. 30, 2016	(4,166)				$ (4,166)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Income (Loss), Net of Tax	$ 1,229					1,229
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Treasury stock acquired	(16.2)	(16,222.0)
Issuance of shares under incentive and stock compensation plans		3,203.0
Return of shares under incentive and stock compensation plans and other to treasury stock		(1,078.0)
Issuance of Shares for Warrant Exercise		192.0
Common Shares Outstanding, at end of period (in thousands) at Jun. 30, 2016		387,916.0
Preferred Stock, Including Additional Paid in Capital [Abstract]
Common Stock, Value, Issued	$ 5	$ 5
Adjustments to Additional Paid in Capital [Abstract]
Additional Paid in Capital	8,897		$ 8,897
Retained Earnings (Accumulated Deficit) [Abstract]
Retained Earnings (Accumulated Deficit)	12,923			$ 12,923
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss), Net of Tax	900					$ 900
Total stockholders' equity	$ 18,559						$ 18,559