LINES OF CREDIT - Other Letters of Credit and Surety Bonds (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Line of Credit Facility [Line Items]
Letters of credit	$ 44	$ 39
Surety bonds	$ 231wy_SuretyBonds	$ 169wy_SuretyBonds

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

No definition available.

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