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Asset Retirement Obligations - MEC - Change in Asset Retirement Obligations (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Beginning Balance $ 753 $ 696
Asset Retirement Obligation, Revision of Estimate 104 3
Asset Retirement Obligation, Liabilities Incurred 59 15
Asset Retirement Obligation, Liabilities Settled 32 8
Asset Retirement Obligation, Accretion Expense 37 35
Asset Retirement Obligation, Current 92 66
Asset Retirement Obligations, Noncurrent 829 687
Ending Balance 921 753
MidAmerican Energy Company [Member]    
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Beginning Balance 460 430
Asset Retirement Obligation, Revision of Estimate 36 (2)
Asset Retirement Obligation, Liabilities Incurred 22 11
Asset Retirement Obligation, Liabilities Settled 9 0
Asset Retirement Obligation, Accretion Expense 23 21
Asset Retirement Obligation, Current 44 28
Asset Retirement Obligations, Noncurrent 488 432
Ending Balance $ 532 $ 460