Commitments and Contingencies, Guarantees (Details) (USD $)	12 Months Ended
	Dec. 31, 2012
Guarantee [Abstract]
Assets held as collateral	$ 0
Payment or Performance Guarantee [Member] | Customer Loans for Farm Rewiring Program [Member]
Guarantee [Abstract]
Guarantee amount	1,000,000	[1]
Current exposure	$ 400,000	[1]
Term or expiration date	2017

[1] The debtor becomes the subject of bankruptcy or other insolvency proceedings.