Components of Accumulated Other Comprehensive Loss, Net - MEC (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance - Accumulated other comprehensive loss, net			$ (1,511)
Other comprehensive income (loss), unrealized gains on available-for-sale securities	$ 81	$ 38	119	$ 71
Other comprehensive income (loss), unrealized gains (losses) on cash flow hedges	(2)	24	(6)	1
Other comprehensive income (loss)	296	(170)	422	(71)
Ending balance - Accumulated other comprehensive loss, net	(1,089)		(1,089)
Accumulated Other Comprehensive (Loss) Income, Net [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance - unrealized gains (losses) on available-for-sale securities			585	615
Beginning balance - unrealized gains (losses) on cash flow hedges			26	7
Beginning balance - Accumulated other comprehensive loss, net			(1,511)	(908)
Other comprehensive income (loss), unrealized gains on available-for-sale securities			119	71
Other comprehensive income (loss), unrealized gains (losses) on cash flow hedges			(6)	1
Other comprehensive income (loss)			422	(71)
Ending balance - unrealized gains (losses) on available-for-sale securities	704	686	704	686
Ending balance - unrealized gains (losses) on cash flow hedges	20	8	20	8
Ending balance - Accumulated other comprehensive loss, net	$ (1,089)	(979)	$ (1,089)	(979)
MidAmerican Energy Company [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other comprehensive income (loss)				2
Dividend, unrealized losses on cash flow hedges, transfer of operations				(90)
MidAmerican Energy Company [Member] | Accumulated Other Comprehensive (Loss) Income, Net [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance - unrealized gains (losses) on available-for-sale securities				(3)
Beginning balance - unrealized gains (losses) on cash flow hedges				(27)
Beginning balance - Accumulated other comprehensive loss, net				(30)
Other comprehensive income (loss), unrealized gains on available-for-sale securities				2
Other comprehensive income (loss), unrealized gains (losses) on cash flow hedges				0
Other comprehensive income (loss)				2
Dividend, unrealized losses on cash flow hedges, transfer of operations				(27)
Ending balance - unrealized gains (losses) on available-for-sale securities		(1)		(1)
Ending balance - unrealized gains (losses) on cash flow hedges		0		0
Ending balance - Accumulated other comprehensive loss, net		$ (1)		$ (1)