INCENTIVE PLANS - Performance Share Units (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Weighted- average grant date fair value per share (in dollars per share):
Granted (in dollars per share)		$ 61.78	$ 73.87
Weighted-average market value, vested (in dollars per share)	$ 79.68
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period used for calculation of performance goals	3 years
Vesting period	3 years
Percentage of target shares earned	100.00%
Number of shares of common stock equivalent to each target share	1
Valuation Assumptions
Expected volatility	22.26%	25.33%	24.93%
Expected dividend yield	2.82%	2.67%	1.75%
Unvested stock awards (in shares):
Beginning balance (in shares)	1,492,000
Granted (in shares)	440,349
Canceled (in shares)	0
Payments (in shares)	(598,546)
Ending balance (in shares)	1,333,803	1,492,000
Weighted- average grant date fair value per share (in dollars per share):
Beginning balance (in dollars per share)	$ 71.69
Granted (in dollars per share)	78.06
Canceled (in dollars per share)	0
Payments (in dollars per share)	59.22
Ending balance (in dollars per share)	79.39	$ 71.69
Weighted-average market value, vested (in dollars per share)	$ 83.45	$ 72.83	$ 83.24
Minimum | Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target shares earned	0.00%
Maximum | Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target shares earned	150.00%