Commitments and Contingencies and Derivative Financial Instruments (Details)	3 Months Ended	12 Months Ended
	Dec. 30, 2022 USD ($)	Sep. 30, 2022 USD ($) derivative_agreement	Sep. 29, 2023 USD ($)	Dec. 22, 2008 case
Fixed Rate Date | Forecast
Loss Contingencies [Line Items]
Aggregate principal amount			$ 500,000,000
Treasury Lock
Loss Contingencies [Line Items]
Number of instruments held | derivative_agreement		2
Derivative notional amount		$ 500,000,000
Derivative assets (liabilities), at fair value	$ 41,500,000	40,900,000
Unrealized gain (loss) on derivatives	30,800,000	31,300,000
Interest Rate Swap and Cross Currency Interest Rate Contract
Loss Contingencies [Line Items]
Derivative assets (liabilities), at fair value	108,000,000	128,200,000
Unrealized gain (loss) on derivatives	80,200,000	87,500,000
Interest Rate Swap
Loss Contingencies [Line Items]
Derivative notional amount	766,700,000
Cross Currency Interest Rate Contract
Loss Contingencies [Line Items]
Derivative notional amount	127,800,000
Foreign Exchange Forward
Loss Contingencies [Line Items]
Derivative notional amount	382,500,000	298,200,000
Derivative assets (liabilities), at fair value	$ 12,100,000	(3,200,000)
Minimum | Cross Currency Interest Rate Contract
Loss Contingencies [Line Items]
Term of derivative contract	3 years 6 months
Minimum | Foreign Exchange Forward
Loss Contingencies [Line Items]
Term of derivative contract	1 month
Maximum | Cross Currency Interest Rate Contract
Loss Contingencies [Line Items]
Term of derivative contract	10 years
Maximum | Foreign Exchange Forward
Loss Contingencies [Line Items]
Term of derivative contract	12 months
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	$ 292,500,000	280,500,000
Surety Bond
Loss Contingencies [Line Items]
Aggregate principal balance of short-term debt	$ 2,000,000,000	$ 2,200,000,000