CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Shares	Treasury Stock	Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Balance (in shares) at Dec. 31, 2018		476	53
Balance at beginning of period at Dec. 31, 2018	$ 2,088	$ 48	$ (1,335)	$ 1,763	$ 4	$ 1,608
Increase (Decrease) in Stockholders' Equity
Net income	681					681
Stock amortization and vesting (in shares)		1
Stock amortization and vesting	19			19
Purchase of treasury stock (in shares)			26
Purchase of treasury stock	(488)		$ (488)
Cash dividends	(146)					(146)
Other comprehensive income	(3)				(3)
Balance (in shares) at Dec. 31, 2019		477	79
Balance at end of period at Dec. 31, 2019	2,151	$ 48	$ (1,823)	1,782	1	2,143
Increase (Decrease) in Stockholders' Equity
Net income	201					201
Stock amortization and vesting (in shares)		1
Stock amortization and vesting	22			22
Cash dividends	(159)					(159)
Other comprehensive income	1				1
Balance (in shares) at Dec. 31, 2020		478	79
Balance at end of period at Dec. 31, 2020	2,216	$ 48	$ (1,823)	1,804	2	2,185
Increase (Decrease) in Stockholders' Equity
Net income	1,158
Issuance of common stock for merger (in shares)		408
Issuance of common stock for merger	9,083	$ 41		9,042
Issuance of replacement awards and options for merger consideration (in shares)		4
Issuance of replacement awards and options for merger consideration	37			37
Exercise of stock appreciation rights	2			2
Stock amortization and vesting (in shares)		3
Stock amortization and vesting	23		$ (3)	26
Cash dividends	(779)					(779)
Preferred stock dividends	(1)					(1)
Other comprehensive income	(1)				(1)
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