SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended									12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Income [Abstract]
Net earnings, basic	$ 184.4	$ 179.5	$ 204.1	$ 164.1	$ 110.0	$ 154.7	$ 169.9	$ 3.0	$ 511.2	$ 732.1	$ 437.6
Net earnings, diluted									$ 511.2	$ 732.1	$ 437.6
Shares [Abstract]
Outstanding shares, basic (in shares)									84.8	102.5	98.8
Dilutive effect of stock options (in shares)									1.1	1.5	1.2
Dilutive effect of restricted stock awards and other (in shares)									0.0	0.0	0.0
Dilutive effect of convertible debt, net of tax (in shares)									0.5	0.3	0.6
Outstanding shares, diluted (in shares)									86.4	104.3	100.6
Per Share Amount [Abstract]
Basic earnings per common share	$ 1.79	$ 1.74	$ 2.00	$ 1.62	$ 1.09	$ 1.53	$ 1.69	$ 0.04	$ 6.03	$ 7.14	$ 4.43
Diluted earnings per share (in dollars per share)	$ 1.75	$ 1.71	$ 1.96	$ 1.58	$ 1.07	$ 1.51	$ 1.66	$ 0.04	$ 5.91	$ 7.02	$ 4.35