Revenue Recognition - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Contract with customer, liability, revenue recognized	$ 222,000,000	$ 193,000,000	$ 1,387,000,000	$ 1,252,000,000
Capitalized contract cost, amortization	66,000,000	48,000,000	188,000,000	145,000,000
Capitalized contract cost, impairment loss	0	$ 0	$ 0	$ 0
Minimum
Disaggregation of Revenue [Line Items]
Contract term			25 years
Maximum
Disaggregation of Revenue [Line Items]
Contract term			35 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-07-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 19,200,000,000		$ 19,200,000,000
Revenue, remaining performance obligation, percentage	65.00%		65.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	2 years		2 years