Commitments and Contingencies and Derivative Financial Instruments (Details) $ in Thousands, $ in Millions			3 Months Ended	6 Months Ended	12 Months Ended
	Apr. 12, 2022 USD ($)	Apr. 12, 2022 AUD ($)	Apr. 01, 2022 USD ($)	Apr. 01, 2022 USD ($)	Oct. 01, 2021 USD ($)	Dec. 31, 2012 MW	Dec. 22, 2008 case
Loss Contingencies [Line Items]
Aggregate principal balance of short-term debt			$ 52,911	$ 52,911	$ 53,456
Interest Rate Swap and Cross Currency Interest Rate Contract
Loss Contingencies [Line Items]
Fair value of derivative assets			60,400	60,400	(800)
Unrealized gain (loss) on derivatives				47,500	7,400
Interest Rate Swap and Cross Currency Interest Rate Contract | Miscellaneous Other Assets
Loss Contingencies [Line Items]
Fair value of derivative assets			62,500	62,500	10,200
Interest Rate Swap and Cross Currency Interest Rate Contract | Other Deferred Liabilities
Loss Contingencies [Line Items]
Fair value of derivative assets			(2,100)	(2,100)	(11,000)
Interest Rate Swap
Loss Contingencies [Line Items]
Derivative notional amount			$ 787,100	$ 787,100
Interest Rate Swap | SONIA Rate
Loss Contingencies [Line Items]
Derivative fixed interest rate			0.82%	0.82%
Cross Currency Interest Rate Contract
Loss Contingencies [Line Items]
Derivative notional amount			$ 127,800	$ 127,800
Cross Currency Interest Rate Contract | LIBOR
Loss Contingencies [Line Items]
Spread on variable rate			0.875%	0.875%
Foreign Exchange Forward
Loss Contingencies [Line Items]
Derivative notional amount			$ 576,500	$ 576,500	506,500
Fair value of derivative assets			2,400	$ 2,400	55,500
Settled amount of hedge			$ 66,700
Minimum | Interest Rate Swap | LIBOR
Loss Contingencies [Line Items]
Derivative fixed interest rate			0.704%	0.704%
Minimum | Cross Currency Interest Rate Contract
Loss Contingencies [Line Items]
Term of derivative contract				3 years 6 months
Derivative fixed interest rate			0.726%	0.726%
Minimum | Foreign Exchange Forward
Loss Contingencies [Line Items]
Term of derivative contract				1 month
Maximum | Interest Rate Swap | LIBOR
Loss Contingencies [Line Items]
Derivative fixed interest rate			1.116%	1.116%
Maximum | Cross Currency Interest Rate Contract
Loss Contingencies [Line Items]
Term of derivative contract				10 years
Derivative fixed interest rate			0.746%	0.746%
Maximum | Foreign Exchange Forward
Loss Contingencies [Line Items]
Term of derivative contract				12 months
General Electric and GE Electrical International Inc | Settled Litigation
Loss Contingencies [Line Items]
Plant capacity (in MW's) | MW						360
JKC Australia LNG Pty Limited | Settled Litigation
Loss Contingencies [Line Items]
Loss related to settlement			$ 91,300	$ 91,300
JKC Australia LNG Pty Limited | Settled Litigation | Subsequent Event
Loss Contingencies [Line Items]
Settlement payment	$ 475,000	$ 640
Kingston Power Plant of the TVA, Secondary Case No. 3:13CV-505-TAV-HBG
Loss Contingencies [Line Items]
Number of pending claims | case							10
LOCs
Loss Contingencies [Line Items]
Aggregate principal balance of short-term debt			274,600	274,600	263,800
Surety Bond
Loss Contingencies [Line Items]
Aggregate principal balance of short-term debt			$ 2,100,000	$ 2,100,000	$ 2,100,000