Revenue Recognition - Performance Obligations and Costs to Obtain or Fulfill a Contract (Details) - USD ($)	3 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 16,500,000,000
Remaining Performance Obligations Expected as Revenue Over the Next Two Years	60.00%
Capitalized Contract Cost, Amortization	$ 50,000,000	$ 41,000,000
Capitalized Contract Cost, Impairment Loss	0	$ 0
Capitalized Contract Cost, Net, Current	149,000,000		$ 149,000,000
Capitalized Contract Cost, Net, Noncurrent	120,000,000		117,000,000
Capitalized Contract Cost, Net	$ 269,000,000		$ 266,000,000

Remaining Performance Obligations Expected as Revenue Over the Next Two Years

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- Definition

Amount of amortization expense for asset recognized from cost incurred to obtain or fulfill contract with customer.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123353750&loc=SL49131252-203054

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- Definition

Amount of impairment loss for asset recognized from cost incurred to obtain or fulfill contract with customer.

+ References

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- Definition

Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123353750&loc=SL49131252-203054

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- Definition

Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer; classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123353750&loc=SL49131252-203054

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- Definition

Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer; classified as noncurrent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123353750&loc=SL49131252-203054

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130556-203045

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