Commitments and Contingencies (Unconditional Purchase Obligations - Narrative) (Details) - USD ($) $ in Billions	Jun. 30, 2022	Sep. 30, 2021
Helium Purchases
Unrecorded Unconditional Purchase Obligation [Line Items]
Unconditional purchase obligation	$ 6.9	$ 8.3

Amount of the unrecorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123406679&loc=d3e25336-109308

Name:	us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceSheetAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant