Accrued Liabilities Table (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accrued Liabilities [Line Items]
Interest on debt	$ 271	$ 288
Employee costs	149	226
Estimated rate refund liabilities	0	189
Contract liabilities (Note 5)	129	158
Asset retirement obligation (Note 11)	63	48
Other, including accrued loss contingencies	304	346
Other accrued liabilities	944	1,276
Accounts Payable and Accrued Liabilities
Accrued Liabilities [Line Items]
Operating lease liabilities (Note 15)	$ 28	$ 21