Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock (Par Value: $0.01)	Preferred Stock (Par Value: $0.01)	Paid-in Capital in Excess of Par	Retained Earnings	Treasury Stock, at Cost	Accumulated Other Comprehensive Loss, Net of Tax
Balance at Dec. 31, 2020	$ 6,842	$ 5	$ 503	$ 6,123	$ 494	$ (258)	$ (25)
Balance, shares at Dec. 31, 2020		463,901,808
Shares issued for restricted stock, net of forfeitures				(28)		28
Shares issued for restricted stock, net of forfeitures, shares		2,515,942
Compensation expense related to restricted stock awards	16			16
Net income	297				297
Dividends paid on common stock	(158)				(158)
Dividends paid on preferred stock	(16)				(16)
Purchase of common stock	(15)					(15)
Purchase of common stock, shares		(1,360,788)
Other comprehensive income (loss), net of tax	(50)						(50)
Balance at Jun. 30, 2021	6,916	$ 5	503	6,111	617	(245)	(75)
Balance, shares at Jun. 30, 2021		465,056,962
Balance at Mar. 31, 2021	6,796	$ 5	503	6,103	552	(245)	(122)
Balance, shares at Mar. 31, 2021		465,074,384
Compensation expense related to restricted stock awards	8			8
Net income	152				152
Dividends paid on common stock	(79)				(79)
Dividends paid on preferred stock	(8)				(8)
Purchase of common stock, shares		(17,422)
Other comprehensive income (loss), net of tax	47						47
Balance at Jun. 30, 2021	6,916	$ 5	503	6,111	617	(245)	(75)
Balance, shares at Jun. 30, 2021		465,056,962
Balance at Dec. 31, 2021	7,044	$ 5	503	6,126	741	(246)	(85)
Balance, shares at Dec. 31, 2021		465,015,643
Shares issued for restricted stock, net of forfeitures				(27)		27
Shares issued for restricted stock, net of forfeitures, shares		2,939,365
Compensation expense related to restricted stock awards	15			15
Net income	326				326
Dividends paid on common stock	(158)				(158)
Dividends paid on preferred stock	(16)				(16)
Purchase of common stock	(19)					(19)
Purchase of common stock, shares		(1,711,930)
Other comprehensive income (loss), net of tax	(368)						(368)
Balance at Jun. 30, 2022	6,824	$ 5	503	6,114	893	(238)	(453)
Balance, shares at Jun. 30, 2022		466,243,078
Balance at Mar. 31, 2022	6,909	$ 5	503	6,107	809	(231)	(284)
Balance, shares at Mar. 31, 2022		467,024,144
Shares issued for restricted stock, net of forfeitures, shares		28,930
Compensation expense related to restricted stock awards	7			7
Net income	171				171
Dividends paid on common stock	(79)				(79)
Dividends paid on preferred stock	(8)				(8)
Purchase of common stock	(7)					(7)
Purchase of common stock, shares		(809,996)
Other comprehensive income (loss), net of tax	(169)						(169)
Balance at Jun. 30, 2022	$ 6,824	$ 5	$ 503	$ 6,114	$ 893	$ (238)	$ (453)
Balance, shares at Jun. 30, 2022		466,243,078