Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Name:	us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

U.S. and Europe Retrospective Responsibility Plans - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017
Restricted Cash and Cash Equivalents Items [Line Items]
Deposits To Litigation Escrow Account	$ (600)
U.S. litigation escrow
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and restricted cash equivalents	$ 902	$ 1,491	$ 1,487	$ 1,031