Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost			$ 1	$ 1
Interest cost	28	18	56	37
Expected return on plan assets	(32)	(40)	(64)	(83)
Amortization of unrecognized net loss	9	8	18	16
Settlements	1	1	1	2
Regulatory asset decrease		1		2
Net periodic (benefit) cost	6	(12)	12	(25)
Other Postretirement Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost		1	1	1
Expected return on plan assets		(1)	(1)	(1)
Net periodic (benefit) cost	$ 0	$ 0	$ 0	$ 0