Held-to-Maturity Securities (Net Premuims) (Details) (Collateralized Mortgage Backed Securities [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Collateralized Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held To Maturity Securities, Premiums	$ 38,670	$ 41,808
Held-to-maturity Securities, Discounts	(36,548)	(24,965)
Held-to-maturity Securities, Premiums (Discounts), Net	$ 2,122	$ 16,843

The amount of debt discount (net of debt premium) that was originally recognized at the issuance of the instrument that has yet to be amortized.

No definition available.

Name:	fhlbcin_HeldToMaturitySecuritiesPremiumDiscountsNet
Namespace Prefix:	fhlbcin_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant