Employee Benefit Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Plan [Member] | UNITED KINGDOM
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	$ 23	$ 20	$ 24
Defined Benefit Plan, Interest Cost	58	72	79
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(100)	(110)	(116)
Defined Benefit Plan, Accumulated Benefit Obligation, (Increase) Decrease for Settlement and Curtailment	31	0	0
Defined Benefit Plan Net Amortization	63	44	62
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	75	26	49
Pension Plan [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Regulatory Deferrals, Before Tax	4	7
Defined Benefit Plan, Service Cost	24	29	33
Defined Benefit Plan, Interest Cost	116	126	121
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(160)	(160)	(169)
Defined Benefit Plan Net Amortization	25	46	53
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	5	41	38
Pension Plan [Member] | Domestic Plan [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	9	10	12
Defined Benefit Plan, Interest Cost	31	34	32
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(44)	(44)	(46)
Defined Benefit Plan Net Amortization	2	2	2
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(2)	2	0
Pension Plan [Member] | Domestic Plan [Member] | MidAmerican Energy Company [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(6)	(2)	(4)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost Not Yet Recognized, Regulatory Deferrals, Before Tax	(7)	(7)
Defined Benefit Plan, Service Cost	9	9	11
Defined Benefit Plan, Interest Cost	29	31	31
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(40)	(41)	(45)
Defined Benefit Plan Net Amortization	(14)	(12)	(11)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(16)	(13)	(14)
Other Postretirement Benefits Plan [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	5	5	7
Defined Benefit Plan, Interest Cost	9	10	9
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(14)	(13)	(15)
Defined Benefit Plan Net Amortization	(4)	(4)	(3)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(4)	(2)	(2)
Other Postretirement Benefits Plan [Member] | MidAmerican Energy Company [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ (1)	$ (1)	$ 0