Income Taxes - Schedule of Breakdown of Income Tax Expense Between Current and Deferred (Details) - USD ($) $ in Millions	3 Months Ended					6 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2023	Sep. 30, 2023	Dec. 31, 2024		Dec. 31, 2023		Dec. 31, 2022
Current:
Federal								$ 873		$ 851		$ 928
State								200		184		203
Subtotal Current								1,073		1,035		1,131
Deferred:
Federal								26		110		151
State								(14)		16		(51)
Subtotal Deferred	$ 7				$ 31	$ 70	$ 97	12	[1]	126	[1]	100	[1]
Total Income Tax Expense	$ 288	$ 262	$ 274	$ 312	$ 313	$ 625	$ 899	$ 1,085	[2]	$ 1,161	[2]	$ 1,231	[2]

[1] See Note 20, Revision of Prior Period Financial Statements.

[2] See Note 20, Revision of Prior Period Financial Statements