Planned Divestiture Of Northwest Operations (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Planned Divestiture Of Northwest Operations [Abstract]
Assets held for sale	$ 1,406	$ 1,401
Loss on disposal of Northwest Operations	$ 24

Amount classified as assets attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer.

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Balance Type:	debit
Period Type:	instant