Deposits (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Deposits [Abstract]
FDIC Deposit Insurance Limit	$ 250,000fcnca_FDICDepositInsuranceLimit
Time Deposits Greater than $250,000, Carrying Value	552,300,000	525,500,000
Deposits, by Type [Abstract]
Demand	8,086,784,000us-gaap_DemandDepositAccounts	5,241,817,000us-gaap_DemandDepositAccounts
Checking With Interest	4,560,565,000	2,445,972,000
Money market accounts	8,319,569,000us-gaap_DepositsMoneyMarketDeposits	6,306,942,000us-gaap_DepositsMoneyMarketDeposits
Savings	1,204,514,000us-gaap_DepositsSavingsDeposits	1,004,097,000us-gaap_DepositsSavingsDeposits
Time	3,507,145,000us-gaap_TimeDeposits	2,875,238,000us-gaap_TimeDeposits
Total deposits	25,678,577,000us-gaap_Deposits	17,874,066,000us-gaap_Deposits
Maturities of Time Deposits [Abstract]
2014	2,423,786,000us-gaap_TimeDepositMaturitiesYearOne
2015	701,043,000us-gaap_TimeDepositMaturitiesYearTwo
2016	241,437,000us-gaap_TimeDepositMaturitiesYearThree
2017	96,949,000us-gaap_TimeDepositMaturitiesYearFour
2018	43,930,000us-gaap_TimeDepositMaturitiesYearFive
Thereafter	$ 0

FDIC Deposit Insurance Limit

No definition available.

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- Definition

Time Deposits Greater than $250,000, Carrying Value

+ References

No definition available.

+ Details

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- Definition

The amount of money in accounts that may bear interest and that the depositor is entitled to withdraw at any time without prior notice.

+ References

+ Details

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- Definition

The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.12)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 9

+ Details

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- Details

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- Details

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- Definition

Amount of deposits in accounts that offer many of the same services as checking accounts although transactions may be somewhat more limited, share some of the characteristics of a money market fund and are insured by the Federal government, also known as money market accounts.

+ References

+ Details

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- Definition

Amount of interest bearing deposits with no stated maturity, which may include passbook and statement savings accounts and money-market deposit accounts (MMDAs).

+ References

+ Details

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- Definition

Amount of interest-bearing domestic checking deposit liabilities.

+ References

+ Details

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- Details

Name:	us-gaap_MaturitiesOfTimeDepositsAbstract
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- Definition

Amount of time deposits maturing after the fifth fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

+ Details

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- Definition

Amount of time deposits maturing in the fifth fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of time deposits maturing in the fourth fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of time deposits maturing in the next fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of time deposits maturing in the third fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of time deposits maturing in the second fiscal year following the latest fiscal year. Time deposits include, but are not limited to, certificates of deposits. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of deposits that cannot be withdrawn before a set date without penalty or for which notice of withdrawal is required. Time deposits include, but are not limited to, certificates of deposits, individual retirement accounts and open accounts.

+ References

+ Details

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