Segment Information (Long-Lived Assets By Geographic Area) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 2,522	$ 2,655
North America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	2,024	2,165
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	451	442
Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 47	$ 48

Amount of long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets, located in foreign countries in total in which the entity holds assets.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 41

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9038-108599

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 38

-Subparagraph b(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_EntityWideDisclosureOnGeographicAreasLongLivedAssetsInForeignCountries
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant