Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 1	$ 1	$ 2	$ 2
Interest cost	20	17	57	53
Expected return on plan assets	(41)	(41)	(124)	(127)
Amortization of unrecognized net loss	8	12	24	37
Settlements			2	2
Regulatory asset (increase) decrease	(1)	1	1	1
Net periodic benefit	(13)	(10)	(38)	(32)
Other Postretirement Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost			1	1
Expected return on plan assets		(1)	(1)	(2)
Net periodic benefit	$ 0	$ (1)	$ 0	$ (1)