Recent Financing Transactions Recent Financing Transactions - Long-Term Debt (Details) £ in Millions, $ in Millions	Oct. 31, 2019 USD ($)	Oct. 31, 2019 GBP (£)	Jun. 30, 2019 USD ($)	May 31, 2019 GBP (£)	Mar. 31, 2019 USD ($)	Feb. 28, 2019 USD ($)	Jan. 31, 2019 USD ($)	Jul. 31, 2018 USD ($)
Northern Natural Gas [Member] | Senior Bonds, 4.30%, due 2049 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 200					$ 450
Debt Instrument, Interest Rate, Stated Percentage			4.30%					4.30%
Northern Electric Plc [Member] | Guaranteed Bonds, 2.75%, due May 2049 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount | £				£ 150
Debt Instrument, Interest Rate, Stated Percentage				2.75%
PacifiCorp [Member] | PAC First Mortgage Bonds, 3.50, Due 2029 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 400
Debt Instrument, Interest Rate, Stated Percentage					3.50%
PacifiCorp [Member] | PAC First Mortgage Bonds, 4.15, Due 2050 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 600
Debt Instrument, Interest Rate, Stated Percentage					4.15%
PacifiCorp [Member] | PAC First Mortgage Bonds, 5.50, Due 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchase Amount					$ 350
Debt Instrument, Interest Rate, Stated Percentage					5.50%
MidAmerican Energy Company [Member] | MEC First Mortgage Bonds, 2.40%, Due March 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage						2.40%
Debt Instrument, Repurchased Face Amount						$ 500
MidAmerican Energy Company [Member] | MEC First Mortgage Bonds, 3.65%, Due April 2029 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount							$ 600
Debt Instrument, Interest Rate, Stated Percentage							3.65%
MidAmerican Energy Company [Member] | MEC First Mortgage Bonds, 4.25%, Due July 2049 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount							$ 900
Debt Instrument, Interest Rate, Stated Percentage							4.25%
Northern Powergrid Holdings [Member] | Bonds, 2.25%, due 2059 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.25%	2.25%
NVE Holdings [Member] | Nevada Power Company [Member] | NPC General and Refunding Mortgage Notes, Series CC [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount							$ 500
Debt Instrument, Interest Rate, Stated Percentage							3.70%
NVE Holdings [Member] | Nevada Power Company [Member] | NPC General and Refunding Mortgage Notes, Series V [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchase Amount							$ 500
Debt Instrument, Interest Rate, Stated Percentage							7.10%
Subsequent Event [Member] | MidAmerican Energy Company [Member] | MEC First Mortgage Bonds, 3.15%, Due April 2050 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 600
Debt Instrument, Interest Rate, Stated Percentage	3.15%	3.15%
Subsequent Event [Member] | MidAmerican Energy Company [Member] | MEC First Mortgage Bonds, 3.65%, Due April 2029 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 250
Debt Instrument, Interest Rate, Stated Percentage	3.65%	3.65%
Subsequent Event [Member] | Northern Powergrid Holdings [Member] | Bonds, 2.25%, due 2059 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount | £		£ 300