STOCK-BASED COMPENSATION - PERFORMANCE STOCK RIGHTS (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Performance Stock Rights
Assumptions incorporated into the valuation models
Risk-free interest rate minimum (as a percent)	0.21%	0.13%	0.17%
Risk-free interest rate maximum (as a percent)	0.63%	1.27%	1.27%
Expected volatility minimum (as a percent)	18.00%	15.00%	14.00%
Expected volatility maximum (as a percent)	22.00%	36.00%	36.00%
Additional Disclosures
Compensation cost not yet recognized	$ 2.0
Weighted-average period over which compensation cost is to be recognized	1 year 7 months
Performance Stock Rights | Minimum
Assumptions incorporated into the valuation models
Expected dividend yield (as a percent)	5.25%	5.28%	5.18%
Performance Stock Rights | Maximum
Assumptions incorporated into the valuation models
Expected dividend yield (as a percent)	5.33%	5.34%	5.34%
Performance Stock Rights Accounted for as Equity Awards
Performance Stock Rights
Outstanding at the beginning of the period (in shares)	5,561
Granted (in shares)	1,113
Award modifications (in shares)	2,295
Distributed (in shares)	(2,235)
Adjustment for estimated payout and shares not distributed (in shares)	(2,831)
Outstanding at the end of the period (in shares)	3,903	5,561
Weighted-Average Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 45.16
Granted (in dollars per share)	$ 44.28	48.50	52.70
Award modifications (in dollars per share)	$ 85.09
Distributed (in dollars per share)	$ 75.02
Adjustment for estimated payout and shares not distributed (in dollars per share)	$ 46.32
Outstanding at the end of the period (in dollars per share)	$ 58.03	45.16
Performance Stock Rights Accounted for as Equity Awards | Performance stock rights with a performance period ending December 31, 2013
Performance Stock Rights
Distributed (in shares)	0
Performance Stock Rights Accounted for as Liability Awards
Performance Stock Rights
Outstanding at the beginning of the period (in shares)	9,222
Granted (in shares)	4,440
Award modifications (in shares)	(2,295)
Distributed (in shares)	(1,240)
Adjustment for estimated payout and shares not distributed (in shares)	(93)
Outstanding at the end of the period (in shares)	10,034
Weighted-Average Fair Value
Outstanding at the end of the period, fair value as of the reporting date (in dollars per share)	$ 121.26
Performance Stock Rights Accounted for as Liability Awards | Performance stock rights with a performance period ending December 31, 2013
Performance Stock Rights
Distributed (in shares)	0