Benefit Plans and Other Postretirement Benefits Net Periodic Benefit Cost (Credit) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Operating and maintenance expenses	$ 2,491,000,000	$ 2,321,000,000	$ 2,324,000,000
transferred	0	0
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	97,000,000	104,000,000	95,000,000
Operating and maintenance expenses	$ 9,000,000	$ 0	$ 7