Consolidated Statements Of Changes In Shareholders' Equity - USD ($) shares in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding shares			203,015
Balance at Dec. 31, 2014	$ 7,369,000,000	$ 1,004,000,000	$ 4,724,000,000	$ 1,769,000,000	$ (128,000,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	309,000,000			309,000,000
Other comprehensive income (loss)	73,000,000				73,000,000
Preferred stock redemption	176,000,000	176,000,000	$ (3,000,000)	3,000,000
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			1,402
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	40,000,000		$ 40,000,000
Dividends on preferred stock	(62,000,000)	(0.22)		(62,000,000)
Dividends on common stock	(45,000,000)			(45,000,000)
Increase (Decrease) in Deferred Compensation	(1,000,000)			(1,000,000)
Balance at Dec. 31, 2015	7,507,000,000	828,000,000	$ 4,767,000,000	1,967,000,000	(55,000,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding shares			204,417
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	469,000,000			469,000,000
Other comprehensive income (loss)	(67,000,000)				(67,000,000)
Preferred stock redemption	$ 126,000,000	118,000,000	$ (2,000,000)	10,000,000
Stock Repurchased During Period, Shares	3,000		(2,889)
Stock Repurchased and Retired During Period, Value	$ (90,000,000)
Subordinated debt converted to preferred stock	(90,000,000)		$ (90,000,000)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			1,557
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	46,000,000		$ 46,000,000
Dividends on preferred stock	(48,000,000)	(0.28)		(48,000,000)
Dividends on common stock	(58,000,000)			(58,000,000)
Increase (Decrease) in Deferred Compensation	1,000,000			1,000,000
Balance at Dec. 31, 2016	$ 7,634,000,000	710,000,000	$ 4,725,000,000	2,321,000,000	(122,000,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding shares	203,085		203,085
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 592,000,000			592,000,000
Other Comprehensive Income (Loss), before Tax	8,000,000				8,000,000
Other comprehensive income (loss)	(17,000,000)
Preferred stock redemption	$ (144,000,000)	(144,000,000)	$ 2,000,000	(2,000,000)
Stock Repurchased During Period, Shares	7,000		(7,009)
Stock Repurchased and Retired During Period, Value	$ (320,000,000)		$ (320,000,000)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			1,456
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	38,000,000		$ 38,000,000
Dividends on preferred stock	(40,000,000)	(0.44)		(40,000,000)
Dividends on common stock	(89,000,000)			(89,000,000)
Effect of new tax rates from Tax Cuts and Jobs Act of 2017	0			25,000,000	(25,000,000)
Balance at Dec. 31, 2017	$ 7,679,000,000	$ 566,000,000	$ 4,445,000,000	$ 2,807,000,000	$ (139,000,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding shares	197,532		197,532