Planned Divestiture Of Northwest Operations (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2019	May 31, 2019
Planned Divestiture Of Northwest Operations [Abstract]
Assets held for sale	$ 1,402	$ 1,402
Consideration amount			$ 1,352
Loss on disposal of Northwest Operations	$ 30	$ 414

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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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant