SUBSEQUENT EVENT (Details) (USD $) In Millions, unless otherwise specified	36 Months Ended
Dec. 31, 2012
Subsequent Events [Abstract]
Pre-tax gain to be recognized during next quarter	$ 5.0

Impairment Charges and Serance Costs, Pre Tax Gain Expected to be Recognized

No definition available.

Name:	fcnca_ImpairmentChargesAndSeranceCostsPreTaxGainExpectedToBeRecognized
Namespace Prefix:	fcnca_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration