Employee Benefit Plans Employee Benefit Plans - MEC - Employer Contributions (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	$ 4
MidAmerican Energy Company [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	1
Employer contributions	0
Domestic Plan [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	39
Employer contributions	4
Domestic Plan [Member] | MidAmerican Energy Company [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	8
Employer contributions	$ 2