STOCK-BASED COMPENSATION – PERFORMANCE STOCK RIGHTS (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Performance stock rights
Assumptions incorporated into the valuation models
Risk-free interest rate, minimum (as a percent)	0.06%
Risk-free interest rate, maximum (as a percent)	0.60%
Expected volatility, minimum (as a percent)	17.00%
Expected volatility, maximum (as a percent)	23.00%
Additional disclosures
Shares distributed for performance stock rights	0
Total intrinsic value of shares distributed during the period		$ 8.8
Tax benefit realized from the distribution of shares		3.6
Compensation cost not yet recognized	$ 5.0
Weighted-average period over which compensation cost is to be recognized	1 year 4 months 19 days
Performance stock rights | Minimum
Assumptions incorporated into the valuation models
Period of historical volatility used to estimate expected volatility	1 year
Expected dividend yield (as a percent)	5.28%
Performance stock rights | Maximum
Assumptions incorporated into the valuation models
Period of historical volatility used to estimate expected volatility	3 years
Expected dividend yield (as a percent)	5.33%
Performance Stock Rights Accounted For As Equity Awards
Performance Stock Rights
Outstanding at the beginning of the period (in shares)	85,749
Granted (in shares)	21,146
Award modifications (in shares)	64,612
Adjustment for shares not distributed	(45,748)
Forfeited (in shares)	(203)
Outstanding at the end of period (in shares)	125,556
Weighted-Average Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 46.62
Granted (in dollars per share)	$ 44.28	$ 48.50
Award modifications (in dollars per share)	$ 85.09
Adjustment for shares not distributed (in dollars per shares)	$ 43.29
Forfeited (in dollars per share)	$ 44.28
Outstanding at the end of the period (in dollars per share)	$ 67.24
Performance Stock Rights Accounted For As Liability Awards
Performance Stock Rights
Outstanding at the beginning of the period (in shares)	198,904
Granted (in shares)	84,529
Award modifications (in shares)	(64,612)
Adjustment for shares not distributed	(39,001)
Forfeited (in shares)	(813)
Outstanding at the end of period (in shares)	179,007
Weighted-Average Fair Value
Outstanding at the end of the period, fair value as of the reporting date (in dollars per share)	$ 78.61