Derivatives (Derivatives Associated with Capital Markets Trading Activities) (Details) (USD $)	Mar. 31, 2015	Mar. 31, 2014
Customer Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional	$ 1,675,215,000	$ 1,775,287,000
Assets	83,797,000	76,173,000
Liabilities	2,241,000	7,103,000
Offsetting Upstream Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional	1,675,215,000	1,775,287,000
Assets	2,241,000	7,103,000
Liabilities	83,797,000	76,173,000
Put Option [Member] \| ShortMember
Derivative Instruments, Gain (Loss) [Line Items]
Notional	7,500,000
Assets	0
Liabilities	12,000
Put Option [Member] \| LongMember
Derivative Instruments, Gain (Loss) [Line Items]
Notional	12,500,000	10,000,000
Assets	60,000	29,000
Liabilities	0	0
Forwards And Futures Purchased [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional	3,181,574,000	2,234,232,000
Assets	5,805,000	1,738,000
Liabilities	538,000	1,260,000
Forwards And Futures Sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional	3,511,607,000	2,607,585,000
Assets	1,105,000	2,277,000
Liabilities	$ 7,290,000	$ 1,478,000

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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- Definition

Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13433-108611

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- Definition

Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities.

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