Regulatory Matters - MEC - Regulatory Assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Regulatory Assets [Line Items]
Regulatory Assets, Noncurrent		$ 3,157	$ 2,766
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided		$ 1,600	1,400
Asset Retirement Obligation Costs
Regulatory Assets [Line Items]
Regulatory asset amortization period years		13 years
Employee benefit plans [Member]
Regulatory Assets [Line Items]
Regulatory asset amortization period years		15
MidAmerican Energy Company [Member]
Regulatory Assets [Line Items]
Regulatory Assets, Noncurrent		$ 392	289
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided		$ 389	286
MidAmerican Energy Company [Member] | Asset Retirement Obligation Costs
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period	[1]	6 years
Regulatory Assets, Noncurrent	[1]	$ 298	223
MidAmerican Energy Company [Member] | Employee benefit plans [Member]
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period	[2]	15 years
Regulatory Assets, Noncurrent	[2]	$ 66	26
MidAmerican Energy Company [Member] | Unrealized loss on regulated derivative contracts [Member]
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period		1 year
Regulatory Assets, Noncurrent		$ 0	7
MidAmerican Energy Company [Member] | Other
Regulatory Assets [Line Items]
Regulatory Assets, Noncurrent		$ 28	$ 33

[1] Amount predominantly relates to AROs for fossil-fueled and wind-powered generating facilities. Refer to Note 11 for a discussion of AROs.

[2] Represents amounts not yet recognized as a component of net periodic benefit cost that are expected to be included in regulated rates when recognized.