Credit Facilities Credit Facilities (Narrative) (Details) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Line of Credit Facility [Line Items]
Line of Credit Facilty - Canada Lease Warehouse Canadian Dollars New	$ 800,000,000
Unamortized Debt Issuance Expense	7,200,000	6,600,000
U.S. Dollar [Member]
Line of Credit Facility [Line Items]
Line of Credit Facilty - Syndicated Warehouse Facilty - Old	2,000,000,000
Line of Credit Facilty -Syndicated warehouse facility	$ 2,500,000,000

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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