CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Millions	Total	Adoption of new accounting standard [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member] Adoption of new accounting standard [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]
Balance at beginning of period at Dec. 31, 2018	$ 4,608		$ 107	$ 3	$ 4,049	$ 576		$ (106)	$ (21)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	223					189		34
Dividends declared:
Preferred stock	(4)					(4)
Common stock	(78)					(78)
Issuance of common stock	(2)				2				(4)
Restricted stock compensation	6				6
Balance at end of period at Jun. 30, 2019	4,753		107	3	4,057	683		(72)	(25)
Balance at beginning of period at Mar. 31, 2019	4,680		107	3	4,052	629		(88)	(23)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	111					95		16
Dividends declared:
Preferred stock	(2)					(2)
Common stock	(39)					(39)
Issuance of common stock	(1)				1				(2)
Restricted stock compensation	4				4
Balance at end of period at Jun. 30, 2019	4,753		107	3	4,057	683		(72)	(25)
Balance at beginning of period at Dec. 31, 2019	4,883	$ (50)	107	3	4,067	798	$ (50)	(65)	(27)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	161					131		30
Dividends declared:
Preferred stock	(4)					(4)
Common stock	(79)					(79)
Issuance of common stock	0				3				(3)
Repurchase of common stock	(25)								(25)
Restricted stock compensation	11				11
Balance at end of period at Jun. 30, 2020	4,897		107	3	4,081	796		(35)	(55)
Balance at beginning of period at Mar. 31, 2020	4,842		107	3	4,075	754		(45)	(52)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	94					84		10
Dividends declared:
Preferred stock	(2)					(2)
Common stock	(40)					(40)
Issuance of common stock	0				3				(3)
Restricted stock compensation	3				3
Balance at end of period at Jun. 30, 2020	$ 4,897		$ 107	$ 3	$ 4,081	$ 796		$ (35)	$ (55)