XML 108 R66.htm IDEA: XBRL DOCUMENT

Commitments, Guarantees and Contingencies - North Dakota Wind Development (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012 Miles kV
DC Transmission Line from Square Butte [Member]
North Dakota Wind Development [Line Items]
Transmission Line Length (Miles)	465
Transmission Line Capacity (kV)	250
Bison Wind Energy Center [Member]
North Dakota Wind Development [Line Items]
Generating Unit Capacity (MW)	292
Bison 1 [Member]
North Dakota Wind Development [Line Items]
Transmission Line Length (Miles)	22
Transmission Line Capacity (kV)	230
Generating Unit Capacity (MW)	82
Capital Cost Spent to Date	174.9
Bison 2 [Member]
North Dakota Wind Development [Line Items]
Generating Unit Capacity (MW)	105
Capital Cost Spent to Date	148.6
Bison 3 [Member]
North Dakota Wind Development [Line Items]
Generating Unit Capacity (MW)	105
Capital Cost Spent to Date	149.8