XML 23 R42.htm IDEA: XBRL DOCUMENT v2.4.0.6

Debt (Details 4) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Debt
Outstanding letters of credit	$ 42	$ 33

X

- Details

Name:	us-gaap_DebtDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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