USE OF DERIVATIVE FINANCIAL INSTRUMENTS, OFFSETTING DISCLOSURES AND CHANGES IN OTHER COMPREHENSIVE INCOME BY COMPONENT - Schedule of Swap Agreements (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2010	Dec. 31, 2013
Notional Disclosures [Abstract]
Derivative instruments unrealized losses to be recognized	$ 12,200,000
Interest Rate SWAP Currently-Paying Contracts [Member]
Notional Disclosures [Abstract]
Notional Amount	7,200,000,000
Average Fixed Rate Payment Requirement (in hundredths)	0.51%
Derivative, average remaining maturity	12 months
Interest Rate SWAP Currently-Paying Contracts [Member] | First Quarter 2015 [Member]
Notional Disclosures [Abstract]
Notional Amount	1,100,000,000
Average Fixed Rate Payment Requirement (in hundredths)	0.50%
Interest Rate SWAP Currently-Paying Contracts [Member] | Second Quarter 2015 [Member]
Notional Disclosures [Abstract]
Notional Amount	200,000,000
Average Fixed Rate Payment Requirement (in hundredths)	0.43%
Interest Rate SWAP Currently-Paying Contracts [Member] | Third Quarter 2015 [Member]
Notional Disclosures [Abstract]
Notional Amount	400,000,000
Average Fixed Rate Payment Requirement (in hundredths)	0.47%
Interest Rate SWAP Currently-Paying Contracts [Member] | Fourth Quarter 2015 [Member]
Notional Disclosures [Abstract]
Notional Amount	1,200,000,000
Average Fixed Rate Payment Requirement (in hundredths)	0.45%
Interest Rate SWAP Currently-Paying Contracts [Member] | First Quarter 2016 [Member]
Notional Disclosures [Abstract]
Notional Amount	1,700,000,000
Average Fixed Rate Payment Requirement (in hundredths)	0.51%
Interest Rate SWAP Currently-Paying Contracts [Member] | Second Quarter 2016 [Member]
Notional Disclosures [Abstract]
Notional Amount	1,100,000,000
Average Fixed Rate Payment Requirement (in hundredths)	0.47%
Interest Rate SWAP Currently-Paying Contracts [Member] | Third Quarter 2016 [Member]
Notional Disclosures [Abstract]
Notional Amount	700,000,000
Average Fixed Rate Payment Requirement (in hundredths)	0.56%
Interest Rate SWAP Currently-Paying Contracts [Member] | Fourth Quarter 2016 [Member]
Notional Disclosures [Abstract]
Notional Amount	800,000,000
Average Fixed Rate Payment Requirement (in hundredths)	0.66%
Interest Rate SWAP Forward-Starting Contracts [Member]
Notional Disclosures [Abstract]
Notional Amount	7,700,000,000
Derivative, average remaining maturity	12 months
Interest Rate SWAP Forward-Starting Contracts [Member] | First quarter 2017 [Member]
Notional Disclosures [Abstract]
Notional Amount	500,000,000
Average Fixed Rate Payment Requirement (in hundredths)	0.72%
Derivative, average remaining maturity	24 months
Interest Rate Swap Agreements [Member]
Derivative Instruments And Hedging Activities [Line Items]
SWAP agreement notional amount during period	2,300,000,000	100,000,000
SWAP agreement average interest rate during period (in hundredths)	0.62%	4.09%
Swap agreement notional amount expiring during period	1,300,000,000
SWAP agreement average interest rate expiring during period (in hundredths)	0.55%
Notional Disclosures [Abstract]
Payment term of LIBOR interest rate agreement	2 years	20 years
Accrued interest	9,500,000		5,500,000
Interest Rate Swap Expired One [Member]
Notional Disclosures [Abstract]
Payment term of LIBOR interest rate agreement	2 years
Interest Rate Swap Expired Two [Member]
Derivative Instruments And Hedging Activities [Line Items]
SWAP agreements notional amount beginning during the period	4,300,000,000
SWAP agreements average interest rate beginning during period (in hundredths)	0.54%
Repurchase Arrangements And Similar Borrowings [Member]
Notional Disclosures [Abstract]
Accrued interest	$ 6,100,000		$ 4,700,000