Document And Entity Information	9 Months Ended
	Sep. 30, 2012	Nov. 09, 2012 Class A Common Stock	Nov. 09, 2012 Class B Common Stock
Entity Registrant Name	FIRST CITIZENS BANCSHARES INC /DE/
Entity Central Index Key	0000798941
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		8,622,022	1,626,937