General Taxes - Components of General Tax Expense from Continuing Operations (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
General Taxes [Abstract]
Gross receipts and franchise	$ 110	$ 112	$ 110
Property and capital stock	124	120	105
Payroll	35	33	31
Other general	11	12	13
Total general taxes	$ 280	$ 277	$ 259

Amount of operating expense for taxes other than income taxes of regulated operation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2(b))
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

Name:	us-gaap_UtilitiesOperatingExpenseTaxes
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration