Employee Benefit Plans Employee Benefit Plans - MEC - Employer Contributions (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017 USD ($)
Domestic Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	$ 15
Employer contributions	7
Domestic Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	5
Employer contributions	4
MidAmerican Energy Company [Member] | Domestic Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	8
Employer contributions	4
MidAmerican Energy Company [Member] | Domestic Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	1
Employer contributions	$ 0