Consolidated Statements of Changes in Stockholders’ Equity (Unaudited) - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Accum. Other Comprehensive Loss	Retained Income
Balance at Beginning of Year at Dec. 31, 2020	$ 14,791	$ 254	$ 2,248	$ (594)	$ 12,883
Comprehensive income:
Net income	673				673
Other comprehensive income	8			8
Total comprehensive income	681
Dividends on common stock,	(249)				(249)
Share repurchases	(591)	(3)	(19)		(569)
Stock-based compensation	11		12		(1)
Balance at End of Period at Mar. 31, 2021	14,643	251	2,241	(586)	12,737
Balance at Beginning of Year at Dec. 31, 2020	14,791	254	2,248	(594)	12,883
Comprehensive income:
Net income	1,492
Other comprehensive income	16
Total comprehensive income	1,508
Share repurchases	(1,500)
Balance at End of Period at Jun. 30, 2021	14,317	248	2,240	(578)	12,407
Balance at Beginning of Year at Mar. 31, 2021	14,643	251	2,241	(586)	12,737
Comprehensive income:
Net income	819				819
Other comprehensive income	8			8
Total comprehensive income	827
Dividends on common stock,	(247)				(247)
Share repurchases	(934)	(3)	(28)		(903)
Stock-based compensation	28		27		1
Balance at End of Period at Jun. 30, 2021	14,317	248	2,240	(578)	12,407
Balance at Beginning of Year at Dec. 31, 2021	13,641	242	2,215	(402)	11,586
Comprehensive income:
Net income	703				703
Other comprehensive income	8			8
Total comprehensive income	711
Dividends on common stock,	(297)				(297)
Share repurchases	(600)	(2)	(19)		(579)
Stock-based compensation	6		7		(1)
Balance at End of Period at Mar. 31, 2022	13,461	240	2,203	(394)	11,412
Balance at Beginning of Year at Dec. 31, 2021	13,641	242	2,215	(402)	11,586
Comprehensive income:
Net income	1,522
Other comprehensive income	14
Total comprehensive income	1,536
Share repurchases	(1,500)
Balance at End of Period at Jun. 30, 2022	13,154	236	2,190	(388)	11,116
Balance at Beginning of Year at Mar. 31, 2022	13,461	240	2,203	(394)	11,412
Comprehensive income:
Net income	819				819
Other comprehensive income	6			6
Total comprehensive income	825
Dividends on common stock,	(294)				(294)
Share repurchases	(854)	(4)	(29)		(821)
Stock-based compensation	16		16
Balance at End of Period at Jun. 30, 2022	$ 13,154	$ 236	$ 2,190	$ (388)	$ 11,116