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Asset Retirement Obligations - MEC - Change in Asset Retirement Obligations (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Beginning Balance $ 921 $ 753
Asset Retirement Obligation, Revision of Estimate 33 104
Asset Retirement Obligation, Liabilities Incurred 25 59
Asset Retirement Obligation, Liabilities Settled (63) (32)
Asset Retirement Obligation, Accretion Expense 38 37
Asset Retirement Obligation, Current 98 92
Asset Retirement Obligations, Noncurrent 856 829
Ending Balance 954 921
MidAmerican Energy Company [Member]    
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Beginning Balance 532 460
Asset Retirement Obligation, Revision of Estimate 28 36
Asset Retirement Obligation, Liabilities Incurred 14 22
Asset Retirement Obligation, Liabilities Settled (32) (9)
Asset Retirement Obligation, Accretion Expense 25 23
Asset Retirement Obligation, Current 57 44
Asset Retirement Obligations, Noncurrent 510 488
Ending Balance $ 567 $ 532