CONDENSED CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Treasury Stock	Paid-In Capital	Accumulated Other Comprehensive Income	Retained Earnings
Beginning balance (in shares) at Dec. 31, 2020		478	(79)
Balance at beginning of period at Dec. 31, 2020	$ 2,216	$ 48	$ (1,823)	$ 1,804	$ 2	$ 2,185
Increase (Decrease) in Stockholders' Equity
Net income	126					126
Stock amortization and vesting	4			4
Common stock cash dividends	(40)					(40)
Ending balance (in shares) at Mar. 31, 2021		478	(79)
Balance at end of period at Mar. 31, 2021	2,306	$ 48	$ (1,823)	1,808	2	2,271
Beginning balance (in shares) at Dec. 31, 2020		478	(79)
Balance at beginning of period at Dec. 31, 2020	2,216	$ 48	$ (1,823)	1,804	2	2,185
Increase (Decrease) in Stockholders' Equity
Share repurchases	(8)
Ending balance (in shares) at Dec. 31, 2021		893	(79)
Balance at end of period at Dec. 31, 2021	11,738	$ 89	$ (1,826)	10,911	1	2,563
Increase (Decrease) in Stockholders' Equity
Net income	608					608
Exercise of stock options	6			6
Stock amortization and vesting	$ 10			10
Share repurchases (in shares)	(8)
Share repurchases	$ (192)
Common stock cash dividends	(455)					(455)
Preferred stock dividends	(1)					(1)
Other comprehensive income	4				4
Ending balance (in shares) at Mar. 31, 2022		893	(87)
Balance at end of period at Mar. 31, 2022	$ 11,718	$ 89	$ (2,018)	$ 10,927	$ 5	$ 2,715