Consolidated Statements of Changes in Stockholders' Equity Consolidated Statement of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Stockholders' Equity, Total [Member]	Common Stocks	Preferred Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock, at Cost	Accumulated Other Comprehensive Loss, net of tax
Preferred Stock, Value, Outstanding				$ 556
Additional Paid in Capital					$ 10,038
Treasury Stock, Value							$ (1,740)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 2,843							$ 2,843
Adjustments to Additional Paid in Capital, Increase in Carrying Amount of Redeemable Preferred Stock				556
Payments for Repurchase of Warrants	(33)				(33)
Stock Issued During Period, Value, Conversion of Convertible Securities					(556)
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	(634)
Stock Issued During Period, Shares, Conversion of Convertible Securities			21,178,000
Balance at beginning of period at Dec. 31, 2012						$ 10,745
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under incentive and stock compensation plans					105
Allocated Share-based Compensation Expense	69
Tax expense on employee stock options and awards					3
Net Income (Loss) Attributable to Parent	176					176
Dividends on preferred stock						(10)
Dividends declared on common stock						(228)
Treasury stock acquired							600
Issuance of shares under incentive and stock compensation plans from treasury stock							125
Return of shares under incentive and stock compensation plans to treasury stock	(20)						(17)
Total other comprehensive income	(2,922)							(2,922)
Balance at end of period at Dec. 31, 2013		$ 18,905				10,683
Common Shares Outstanding, at beginning of period at Dec. 31, 2012			436,306,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock acquired			(19,235,000)
Issuance of shares under incentive and stock compensation plans			2,136,000
Return of shares under incentive and stock compensation plans and other to treasury stock			(592,000)
Common Shares Outstanding, at end of period at Dec. 31, 2013			453,290,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustments to Additional Paid in Capital, Stock Issued, Own-share Lending Arrangement, Issuance Costs	634
Stock Issued During Period, Shares, Warrant Exercised			13,497,000
Preferred Stock, Value, Outstanding				0
Common Stock, Value, Issued			$ 5
Additional Paid in Capital					9,894
Treasury Stock, Value							(1,598)
Retained Earnings (Accumulated Deficit)						10,683
Accumulated Other Comprehensive Income (Loss), Net of Tax	(79)							(79)
Adjustments to Additional Paid in Capital, Increase in Carrying Amount of Redeemable Preferred Stock				0
Payments for Repurchase of Warrants					0
Stock Issued During Period, Value, Conversion of Convertible Securities					0
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs					(801)
Stock Issued During Period, Shares, Conversion of Convertible Securities			0
Issuance of shares under incentive and stock compensation plans					64
Allocated Share-based Compensation Expense	98				88
Tax expense on employee stock options and awards					6
Net Income (Loss) Attributable to Parent	798					798
Dividends on preferred stock						0
Dividends declared on common stock						(290)
Treasury stock acquired							1,796
Issuance of shares under incentive and stock compensation plans from treasury stock							82
Return of shares under incentive and stock compensation plans to treasury stock	(30)						(16)
Total other comprehensive income	1,007							1,007
Balance at end of period at Dec. 31, 2014	18,720	18,720
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock acquired			(49,518,000)
Issuance of shares under incentive and stock compensation plans			2,003,000
Return of shares under incentive and stock compensation plans and other to treasury stock			(439,000)
Common Shares Outstanding, at end of period at Dec. 31, 2014			424,416,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustments to Additional Paid in Capital, Stock Issued, Own-share Lending Arrangement, Issuance Costs							801
Stock Issued During Period, Shares, Warrant Exercised			19,080,000
Preferred Stock, Value, Outstanding				0
Common Stock, Value, Issued	5		$ 5
Additional Paid in Capital	9,123				9,123
Treasury Stock, Value	(2,527)						(2,527)
Retained Earnings (Accumulated Deficit)	11,191					11,191
Accumulated Other Comprehensive Income (Loss), Net of Tax	928							928
Adjustments to Additional Paid in Capital, Increase in Carrying Amount of Redeemable Preferred Stock				0
Payments for Repurchase of Warrants	0				0
Stock Issued During Period, Value, Conversion of Convertible Securities					0
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs					(90)
Stock Issued During Period, Shares, Conversion of Convertible Securities			0
Issuance of shares under incentive and stock compensation plans					165
Allocated Share-based Compensation Expense	78				78
Tax expense on employee stock options and awards					27
Net Income (Loss) Attributable to Parent	1,682					1,682
Dividends on preferred stock						0
Dividends declared on common stock						(323)
Treasury stock acquired							1,250
Issuance of shares under incentive and stock compensation plans from treasury stock							184
Return of shares under incentive and stock compensation plans to treasury stock	(42)						(54)
Total other comprehensive income	(1,257)							(1,257)
Balance at end of period at Dec. 31, 2015	17,642	$ 17,642
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock acquired			(28,431,000)
Issuance of shares under incentive and stock compensation plans			4,877,000
Return of shares under incentive and stock compensation plans and other to treasury stock			(1,311,000)
Common Shares Outstanding, at end of period at Dec. 31, 2015			401,821,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustments to Additional Paid in Capital, Stock Issued, Own-share Lending Arrangement, Issuance Costs							90
Stock Issued During Period, Shares, Warrant Exercised			2,270,000
Preferred Stock, Value, Outstanding				$ 0
Common Stock, Value, Issued	5		$ 5
Additional Paid in Capital	8,973				$ 8,973
Treasury Stock, Value	(3,557)						$ (3,557)
Retained Earnings (Accumulated Deficit)	12,550					$ 12,550
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (329)							$ (329)