Consolidated Statement of Changes in Equity - USD ($) $ in Millions	Total	Common stock and paid-in capital [Member]	Preferred stock [Member]	Accumulated deficit [Member]	Accumulated other comprehensive (loss) income [Member]	Treasury stock [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (66)				$ (66)
Stockholders' Equity Attributable to Parent, Total at Dec. 31, 2014	15,399	$ 21,038	$ 1,255	$ (6,828)		$ 0
Net Income (Loss) Attributable to Parent	1,026			1,026
Dividends, Preferred Stock, Cash	(1,356)			(1,356)
Stock Repurchased During Period, Value	(325)		(325)
Preferred stock redemption	(117)		(117)
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	44	44
Other Comprehensive Income (Loss), Net of Tax	(56)				(56)
Treasury Stock, Value, Acquired, Cost Method	(16)					(16)
Stockholders' Equity Attributable to Parent, Total at Sep. 30, 2015	14,599	21,082	813	(7,158)		(16)
Stock Repurchase and Redemption Premium	1,193
Accumulated Other Comprehensive Income (Loss), Net of Tax	(122)				(122)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(231)				(231)
Stockholders' Equity Attributable to Parent, Total at Dec. 31, 2015	13,439	21,100	696	(8,110)		(16)
Net Income (Loss) Attributable to Parent	819
Dividends, Preferred Stock, Cash	(30)			(30)
Stock Repurchased During Period, Value	(696)		(696)
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	49	49
Other Comprehensive Income (Loss), Net of Tax	262				262
Treasury Stock, Value, Acquired, Cost Method	(173)					(173)
Dividends, Common Stock, Cash	(40)			(40)
Stockholders' Equity Attributable to Parent, Total at Sep. 30, 2016	13,630	$ 21,149	$ 0	$ (7,361)		$ (189)
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 31				$ 31