Commitments and Contingencies, Guarantees (Details) - Payment or Performance Guarantee - Customer Loans for Farm Rewiring Program	12 Months Ended
	Dec. 31, 2017 USD ($)
Guarantee [Abstract]
Assets held as collateral	$ 0
Guarantees issued and outstanding	1,000,000	[1],[2]
Current exposure under these guarantees	$ 0	[1],[2]
Guarantee Expiration Date (year)	2020	[1],[2]
Guarantee Obligations Claims made	$ 0

[1] (a) The term of this guarantee expires in 2020, which is the final scheduled repayment date for the loans. As of Dec. 31, 2017, no claims had been made by the lender.

[2] (b) The debtor becomes the subject of bankruptcy or other insolvency proceedings.