Earnings Per Share and Stock Issuances-Additional Information (Details) (USD $) In Millions, unless otherwise specified	Feb. 28, 2015
Earnings Per Share, Basic and Diluted [Abstract]
Stock repurchase program, remaining authorized repurchase amount	$ 51
Stock Repurchase Program, Authorized Amount	$ 400

Amount remaining of a stock repurchase plan authorized.

No definition available.

Name:	us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant