Auto Loan Receivables (Allowance For Loan Losses) (Details) - USD ($) $ in Millions	3 Months Ended
May 31, 2018	May 31, 2017	Feb. 28, 2018	Feb. 28, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance as of beginning of period	$ 128.6	$ 123.6
Charge-offs	(58.9)	(54.1)
Recoveries	33.7	31.7
Provision for loan losses	30.9	28.6
Balance as of end of period	$ 134.3	$ 129.8
Allowance For Loan Losses, percent
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Item as percent of total ending managed receivables	1.13%	1.18%	1.11%	1.16%

Item as percent of total ending managed receivables

No definition available.

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

A valuation allowance for financing receivables that are expected to be uncollectible.

+ References

+ Details

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

- Definition

Amount of recovery of financing receivables doubtful of collection that were previously charged off.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of direct write-downs of financing receivables charged against the allowance.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=us-gaap_AllowanceForLoanAndLeaseLossesMember
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Balance Type:
Period Type: