Income Taxes Schedule of Deferred tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred income tax assets:
Employee benefits	$ 119	$ 134
Price risk management	26	36
Deferred income taxes	22	26
Deferred Tax Assets, tax credits, net of valuation allowance	64	52
Deferred Tax Assets, Tax Deferred Expense, Other	0	9
Total deferred income tax assets	231	257
Deferred income tax liabilities:
Depreciation and amortization	496	511
Regulatory assets	103	115
Deferred Tax Liabilities, Other	10	0
Deferred Tax Liabilities, Gross, Noncurrent	609	626
Total deferred income tax liabilities	$ 378	$ 369