Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 1	$ 1
Interest cost	28	19
Expected return on plan assets	(32)	(43)
Amortization of unrecognized net loss	9	8
Settlements		1
Regulatory asset decrease		1
Net periodic (benefit) cost	6	(13)
Other Postretirement Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost
Interest cost	1
Expected return on plan assets	(1)
Amortization of unrecognized net loss
Settlements
Regulatory asset decrease
Net periodic (benefit) cost	$ 0	$ 0