Document And Entity Information	3 Months Ended
	Mar. 31, 2012	May 10, 2012 Class A Common Stock [Member]	May 10, 2012 Class B Common Stock [Member]
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	Mar. 31, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		8,644,307	1,626,937