Fair Value of Financial Instruments Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Surrender Value, Fair Value Disclosure	$ 31		$ 31		$ 36
net realized loss	1			$ 2
Long-term Debt	3,286		3,286		3,285
Unamortized Debt Issuance Expense	13		13		14
Long-term Debt, Fair Value	3,092		3,092		$ 3,831
Net gain or loss recognized in the statement of income offset by regulatory accounting	15	$ (112)	(183)	$ (151)
net realized gains	$ 2		$ 3