Amount of cash and cash equivalents restricted as to withdrawal or usage. 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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Name:	us-gaap_RestrictedCashAndCashEquivalents
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Asset Securitizations (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Assets from Trusts [Line Items]
Restricted cash included in Other assets per Consolidated Balance Sheets	$ 454.0	$ 363.0	$ 414.0	$ 336.0
Variable Interest Entity
Assets from Trusts [Line Items]
Restricted cash included in Other assets per Consolidated Balance Sheets	84.0	70.0
American Express Charge Trust [Member] \| Variable Interest Entity
Assets from Trusts [Line Items]
Restricted cash included in Other assets per Consolidated Balance Sheets	1.0	3.0
American Express Lending Trust [Member] \| Variable Interest Entity
Assets from Trusts [Line Items]
Restricted cash included in Other assets per Consolidated Balance Sheets	$ 83.0	$ 67.0