Employee Benefit Plans - MEC - Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	$ 666	$ 662
Defined Benefit Plan, Plan Assets, Contributions by Employer	5	2
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	10	10
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	106	41
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(51)	(49)
Ending balance	736	666	$ 662
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	734	740
Defined Benefit Plan, Service Cost	9	9	11
Defined Benefit Plan, Interest Cost	29	31	31
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	10	10
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	(10)	(7)
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(51)	(49)
Ending balance	721	734	740
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	15	(68)
Assets for Plan Benefits, Defined Benefit Plan	32	19
Other current liabilities	0	0
Liability, Defined Benefit Plan, Noncurrent	(17)	(87)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	15	(68)
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plans, Supplemental Employee Retirement Plans [Abstract]
Life Insurance, Corporate or Bank Owned, Amount	272	242
MidAmerican Energy Company [Member]
Defined Benefit Plans, Supplemental Employee Retirement Plans [Abstract]
Life Insurance, Corporate or Bank Owned, Amount	198	184
MidAmerican Energy Company [Member] | Pension Plan [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	684
Ending balance	745	684
MidAmerican Energy Company [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	252	249
Defined Benefit Plan, Plan Assets, Contributions by Employer	1	1
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	1	1
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	36	14
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(13)	(13)
Ending balance	277	252	249
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	233	234
Defined Benefit Plan, Service Cost	5	5	7
Defined Benefit Plan, Interest Cost	9	10	9
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	1	1
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	11	(4)
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(13)	(13)
Ending balance	246	233	234
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	31	19
Assets for Plan Benefits, Defined Benefit Plan	31	19
Other current liabilities	0	0
Liability, Defined Benefit Plan, Noncurrent	0	0
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	31	19
MidAmerican Energy Company [Member] | MidAmerican Energy Company [Member] | Supplemental Employee Retirement Plan [Member]
Defined Benefit Plans, Supplemental Employee Retirement Plans [Abstract]
Life Insurance, Corporate or Bank Owned, Amount	118	110
Domestic Plan [Member] | Pension Plan [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	2,525	2,489
Defined Benefit Plan, Plan Assets, Contributions by Employer	64	78
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	390	163
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(203)	(194)
Ending balance	2,761	2,525	2,489
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	2,952	2,934
Defined Benefit Plan, Service Cost	24	29	33
Defined Benefit Plan, Interest Cost	116	126	121
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	0	0
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	132	67
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(203)	(194)
Ending balance	3,006	2,952	2,934
Defined Benefit Plan, Accumulated Benefit Obligation	2,988	2,929
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(245)	(427)
Assets for Plan Benefits, Defined Benefit Plan	66	26
Other current liabilities	(14)	(15)
Liability, Defined Benefit Plan, Noncurrent	(297)	(438)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(245)	(427)
Domestic Plan [Member] | MidAmerican Energy Company [Member] | Pension Plan [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	684	678
Defined Benefit Plan, Plan Assets, Contributions by Employer	7	7
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	114	57
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(60)	(58)
Ending balance	745	684	678
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	773	785
Defined Benefit Plan, Service Cost	9	10	12
Defined Benefit Plan, Interest Cost	31	34	32
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	0	0
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	46	2
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(60)	(58)
Ending balance	799	773	$ 785
Defined Benefit Plan, Accumulated Benefit Obligation	790	764
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(54)	(89)
Assets for Plan Benefits, Defined Benefit Plan	66	26
Other current liabilities	(8)	(8)
Liability, Defined Benefit Plan, Noncurrent	(112)	(107)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	$ (54)	$ (89)