Derivative Financial Instruments (Narrative) (Details) (USD $) In Billions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional amounts on foreign currency exchange forward contracts outstanding	$ 3.90	$ 4.03

Aggregate notional amount of all derivatives. The notional amount relates to a number of currency units, shares, bushels, pounds, or other units specified in a derivative instrument.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Notional Amount

-URI http://asc.fasb.org/extlink&oid=6519104

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