Winter Storm Uri (Details) - USD ($) $ in Thousands		1 Months Ended
	Oct. 25, 2022	Feb. 28, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 14, 2021	Jul. 30, 2021	Mar. 31, 2021	Mar. 09, 2021
Unusual or Infrequent Item, or Both [Line Items]
Aggregate natural gas purchases		$ 2,300,000
Regulatory assets			$ 2,605,372	$ 2,521,441
Winter Storm Uri incremental costs
Unusual or Infrequent Item, or Both [Line Items]
Regulatory assets			2,109,454	$ 2,100,728
Winter Storm Uri incremental costs | Winter Storm Uri
Unusual or Infrequent Item, or Both [Line Items]
Regulatory assets			2,100,000
Winter Storm Uri incremental costs | Kansas | Winter Storm Uri
Unusual or Infrequent Item, or Both [Line Items]
Regulatory assets			88,500
Winter Storm Uri incremental costs | Texas | Winter Storm Uri
Unusual or Infrequent Item, or Both [Line Items]
Regulatory assets			$ 2,021,000
Extraordinary Gas Cost | Kansas | Subsequent Event
Unusual or Infrequent Item, or Both [Line Items]
Regulatory asset, authorized	$ 118,500
Regulatory asset, amortization period	12 years
Extraordinary Gas Cost | Kansas | Winter Storm Uri
Unusual or Infrequent Item, or Both [Line Items]
Regulatory assets					$ 94,100
Extraordinary Gas Cost | Texas | Winter Storm Uri
Unusual or Infrequent Item, or Both [Line Items]
Regulatory assets						$ 2,000,000
Senior Notes Due 2023
Unusual or Infrequent Item, or Both [Line Items]
Debt instrument, face amount							$ 2,200,000	$ 2,200,000
Administrative costs							$ 600