Supplemental Cash Flow Information (Details) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020
Supplemental Cash Flow Information [Abstract]
Interest (1)	[1]	$ 102	$ 69
Income Taxes, Net of Refunds Received		507	(76)
Interest Costs Capitalized		15	17
Accrued Capital Expenditures		445	246
Non-Cash Property Exchanges		25	55
Noncash Additions To Other Property, Plant and Equipment		$ 74	$ 73

[1] Net of capitalized interest of $15 million and $17 million for the six months ended June 30, 2021 and 2020, respectively.