Employee Benefits - Change in Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Change in plan assets
Return on plan assets	$ (987)	$ 422
Combined Pension Plan
Change in plan assets
Fair value of plan assets at beginning of year	8,531	10,546	$ 10,493
Plan spin-off	(2,239)	0	0
Return on plan assets	(987)	422	1,210
Benefits paid from plan assets	(590)	(766)	(1,157)
Settlement payments and annuity purchase	0	(1,671)	0
Fair value of plan assets at end of year	$ 4,715	$ 8,531	$ 10,546