Leases (Schedule Of Lease Assets and Liabilities Recorded in Consolidated Balance Sheets) (Detail) - USD ($) $ in Millions		Dec. 31, 2019		Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease assets		$ 23	[1]	$ 19
Finance lease assets	[2]	26
Total lease assets		49
Operating lease liabilities - current	[3]	3
Operating lease liabilities - noncurrent	[4]	20
Finance lease liabilities - current	[5]	7
Finance lease liabilities - noncurrent		20			$ 0
Total lease liabilities		$ 50

[1] Included in other deferred debits and other assets in the Consolidated Balance Sheets.

[2] Included in utility plant, net, in the Consolidated Balance Sheets, net of $24 million of accumulated amortization at December 31, 2019.

[3] Included in other current liabilities in the Consolidated Balance Sheets.

[4] Included in other deferred credits and other liabilities in the Consolidated Balance Sheets.

[5] Included in current portion of long-term debt in the Consolidated Balance Sheets.