Supplemental Cash Flow Information (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020
Supplemental Cash Flow Information [Abstract]
Interest (1)	[1]	$ 134	$ 152
Income Taxes, Net of Refunds Received		775	(263)
Interest Costs Capitalized		24	24
Accrued Capital Expenditures		405	244
Non-Cash Property Exchanges		41	135
Noncash Additions To Other Property, Plant and Equipment		$ 74	$ 73

[1] Net of capitalized interest of $24 million for both the nine months ended September 30, 2021 and 2020.