Summary of Significant Accounting Policies - PacifiCorp - Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning balance	$ 31
Ending balance	33	$ 31
PacifiCorp [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning balance	7	7
Ending balance	7	7	$ 7
Allowance for Doubtful Accounts [Member] | PacifiCorp [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning balance	7	7	8
Charged to operating costs and expenses, net	12	10	11
Write-offs, net	$ 12	10	12
Ending balance		$ 7	$ 7