Fair Value of Financial Instruments (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Mar. 31, 2014
Fair Value Disclosures [Abstract]
Fair value of junior subordinated convertible debentures based on the trading price of the bonds	$ 2,137	$ 2,138

Fair value portion of borrowing which can be exchanged for a specified number of another security at the option of the issuer or the holder, for example, but not limited to, the entity's common stock.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Convertible Security

-URI http://asc.fasb.org/extlink&oid=6509036

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