Employee Benefit Plans - MEC (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Pension Plan [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4	$ 4	$ 11	$ 12
Interest cost	23	27	69	82
Expected return on plan assets	(35)	(38)	(105)	(115)
Net amortization	8	8	25	24
Net periodic benefit cost	0	1	0	3
Pension Plan [Member] | UNITED STATES | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2	4	5
Interest cost	7	7	19	22
Expected return on plan assets	(10)	(10)	(30)	(31)
Net amortization	0	0	1	0
Net periodic benefit cost	(1)	(1)	(6)	(4)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	5	6
Interest cost	6	6	16	20
Expected return on plan assets	(9)	(10)	(25)	(30)
Net amortization	(1)	0	(5)	(3)
Net periodic benefit cost	(3)	(3)	(9)	(7)
Other Postretirement Benefits Plan [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	3	4
Interest cost	2	2	5	7
Expected return on plan assets	(4)	(3)	(10)	(9)
Net amortization	(1)	(1)	(4)	(3)
Net periodic benefit cost	$ (2)	$ (1)	$ (6)	$ (1)