Cash and Cash Equivalents and Restricted Cash and Cash Equivalents Supplemental Cash Flow Disclosure - Pacificorp (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents	$ 1,016	$ 935
Restricted cash and cash equivalents	358	327
Restricted Cash and Cash Equivalents, Noncurrent	28	21
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	1,402	1,283	$ 1,459	$ 1,003
PacifiCorp [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents	308	14
Restricted cash and cash equivalents	13	13
Restricted Cash and Cash Equivalents, Noncurrent	2	2
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	323	$ 29	$ 119	$ 33
Accounting Standards Update 2016-15 [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Prior Period Reclassification Adjustment	26
Accounting Standards Update 2016-15 [Member] | PacifiCorp [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Prior Period Reclassification Adjustment	$ 26