Employee Benefit Plans - MEC - Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	$ 742	$ 664
Defined Benefit Plan, Plan Assets, Contributions by Employer	3	2
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	8	9
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	40	122
Defined Benefit Plan, Plan Assets, Payment for Settlement	0	0
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(49)	(55)
Ending balance	744	742	$ 664
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	673	672
Defined Benefit Plan, Service Cost	7	8	9
Defined Benefit Plan, Interest Cost	21	27	24
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	8	9
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	61	12
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	0
Defined Benefit Plan, Benefit Obligation, Business Combination	37	0
Defined Benefit Plan, Benefit Obligation, Payment for Settlement	0	0
Benefits Paid	(49)	(55)
Ending balance	758	673	672
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(14)	69
Assets for Plan Benefits, Defined Benefit Plan	20	76
Other current liabilities	0	0
Liability, Defined Benefit Plan, Noncurrent	(34)	(7)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(14)	69
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plans, Supplemental Employee Retirement Plans [Abstract]
Life Insurance, Corporate or Bank Owned, Amount	303	252
MidAmerican Energy Company [Member]
Defined Benefit Plans, Supplemental Employee Retirement Plans [Abstract]
Life Insurance, Corporate or Bank Owned, Amount	211	203
MidAmerican Energy Company [Member] | Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation, Business Combination	81
MidAmerican Energy Company [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	272	247
Defined Benefit Plan, Plan Assets, Contributions by Employer	3	1
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	1	2
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	15	42
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(13)	(20)
Ending balance	278	272	247
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	226	242
Defined Benefit Plan, Service Cost	4	5	5
Defined Benefit Plan, Interest Cost	7	10	8
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	1	2
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	42	(13)
Defined Benefit Plan, Benefit Obligation, Business Combination	37	0
Benefits Paid	(13)	(20)
Ending balance	304	226	242
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(26)	46
Assets for Plan Benefits, Defined Benefit Plan	0	46
Other current liabilities	0	0
Liability, Defined Benefit Plan, Noncurrent	(26)	0
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(26)	46
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	130	122
UNITED STATES | Pension Plan [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	2,656	2,396
Defined Benefit Plan, Plan Assets, Contributions by Employer	13	12
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	373	456
Defined Benefit Plan, Plan Assets, Payment for Settlement	0	(22)
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(218)	(186)
Ending balance	2,824	2,656	2,396
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	2,878	2,718
Defined Benefit Plan, Service Cost	17	16	21
Defined Benefit Plan, Interest Cost	93	111	105
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	0	0
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	226	242
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	(1)
Defined Benefit Plan, Benefit Obligation, Business Combination	81	0
Defined Benefit Plan, Benefit Obligation, Payment for Settlement	0	22
Benefits Paid	(218)	(186)
Ending balance	3,077	2,878	2,718
Defined Benefit Plan, Accumulated Benefit Obligation	2,999	2,867
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(253)	(222)
Assets for Plan Benefits, Defined Benefit Plan	43	73
Other current liabilities	(13)	(13)
Liability, Defined Benefit Plan, Noncurrent	(283)	(282)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(253)	(222)
UNITED STATES | MidAmerican Energy Company [Member] | Pension Plan [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	717	644
Defined Benefit Plan, Plan Assets, Contributions by Employer	6	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)	55	123
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(60)	(57)
Ending balance	718	717	644
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	763	736
Defined Benefit Plan, Service Cost	8	6	9
Defined Benefit Plan, Interest Cost	25	30	28
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	0	0
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	28	48
Defined Benefit Plan, Benefit Obligation, Business Combination	81	0
Benefits Paid	(60)	(57)
Ending balance	845	763	$ 736
Defined Benefit Plan, Accumulated Benefit Obligation	773	758
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(127)	(46)
Assets for Plan Benefits, Defined Benefit Plan	0	66
Other current liabilities	(7)	(7)
Liability, Defined Benefit Plan, Noncurrent	(120)	(105)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(127)	(46)
UNITED STATES | MidAmerican Energy Company [Member] | Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	112
Ending balance	117	112
Defined Benefit Plan, Accumulated Benefit Obligation	$ 117	$ 112