XML 49 R59.htm IDEA: XBRL DOCUMENT

Commitments, Guarantees and Contingencies - North Dakota Wind Development (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014 kV Miles
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 Capacity (MW)	292
Bison 4 [Member]
North Dakota Wind Development [Line Items]
Generating Capacity (MW)	205
Estimated Capital Expenditures	$ 345
Capital Cost Spent to Date	$ 187.1