PARENT-ONLY FINANCIAL STATEMENTS (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets:
Cash and cash equivalents	$ 3,874.4				$ 3,817.4				$ 3,874.4	$ 3,817.4
Total assets	26,494.8				30,387.7				26,494.8	30,387.7
Liabilities:
Total liabilities	24,906.5				28,055.6				24,906.5	28,055.6
Stockholders' equity	1,588.3				2,332.1				1,588.3	2,332.1	$ 1,855.3	$ 1,658.2
Total liabilities and equity	26,494.8				30,387.7				26,494.8	30,387.7
Statements of Income
Total revenue	1,461.0	$ 1,437.6	$ 1,348.5	$ 1,334.2	1,464.5	$ 1,423.2	$ 1,397.2	$ 1,381.7	5,581.3	5,666.6	5,474.7
Loss on extinguishment of debt									71.9
Interest expense, net	141.6	140.0	143.5	143.9	144.7	136.8	133.6	127.2	569.0	542.3	455.4
Income (loss) before income taxes and equity in undistributed net income of subsidiaries	167.4	164.2	193.8	213.0	363.8	343.0	263.1	245.1	738.4	1,215.0	1,062.5
Benefit for income taxes	(37.0)	(42.6)	(51.4)	(34.8)	(110.7)	(54.3)	(39.3)	(65.2)	(165.8)	(269.5)	(293.3)
Net income									278.0	963.1	788.7
(Loss) income from discontinued operations, net of tax	(32.9)	$ (229.2)	$ (3.4)	(29.1)	31.8	$ 7.8	$ (6.0)	(16.0)	(294.6)	17.6	19.5
Other comprehensive income:
Net income									278.0	963.1	788.7
Other comprehensive income									38.2	2.1	10.5
Statements of Cash Flows
Net cash (used in) provided by operating activities									1,217.7	2,754.9	2,599.1
Investing activities:
Proceeds from sale of business									4,409.7
Net cash provided by (used in) investing activities									2,860.8	(1,872.0)	(4,268.1)
Financing activities:
Payment of debt extinguishment costs									(46.1)
Payment of deferred financing costs									(45.4)	(25.8)	(65.7)
Purchase of treasury shares									(976.1)	(443.2)	(553.7)
Dividends paid									(127.4)	(125.2)	(115.5)
Proceeds from issuance of common stock									12.4	17.6	18.4
Other									(27.0)	(31.3)	(29.3)
Net cash (used in) provided by financing activities									(4,091.7)	(1,217.9)	4,004.9
Change in cash, cash equivalents and restricted cash									(9.6)	(347.0)	2,346.2
Cash, cash equivalents and restricted cash at beginning of year				3,967.7				4,314.7	3,967.7	4,314.7	1,968.5
Cash, cash equivalents and restricted cash at end of year	3,958.1				3,967.7				3,958.1	3,967.7	4,314.7
Parent company
Assets:
Cash and cash equivalents	0.2				0.1				0.2	0.1
Investment in subsidiaries	5,326.2				8,606.0				5,326.2	8,606.0
Other assets	3.4				20.1				3.4	20.1
Total assets	5,329.8				8,626.2				5,329.8	8,626.2
Liabilities:
Current portion of long-term and other debt	101.4				114.4				101.4	114.4
Long-term debt	2,748.5				5,427.7				2,748.5	5,427.7
Intercompany liabilities	806.7				395.9				806.7	395.9
Other liabilities	84.9				356.1				84.9	356.1
Total liabilities	3,741.5				6,294.1				3,741.5	6,294.1
Stockholders' equity	1,588.3				2,332.1				1,588.3	2,332.1
Total liabilities and equity	5,329.8				8,626.2				5,329.8	8,626.2
Statements of Income
Interest from loans to subsidiaries									19.2	17.9	13.8
Dividends from subsidiaries									922.6	810.1	360.6
Total revenue									941.8	828.0	374.4
Loss on extinguishment of debt									71.9
Interest expense, net									130.0	281.2	278.9
Other expenses, net									(0.7)	(0.4)	12.9
Total expenses									201.2	280.8	291.8
Income (loss) before income taxes and equity in undistributed net income of subsidiaries									740.6	547.2	82.6
Benefit for income taxes									42.1	7.0	322.7
Income before equity in undistributed net income of subsidiaries									782.7	554.2	405.3
Equity in undistributed net income of subsidiaries									(504.7)	408.9	383.4
Net income									278.0	963.1	788.7
(Loss) income from discontinued operations, net of tax									(252.1)
Other comprehensive income:
Net income									278.0	963.1	788.7
Other comprehensive income									4.9	29.6	(46.1)
Total comprehensive income, net of tax									282.9	992.7	742.6
Statements of Cash Flows
Net cash (used in) provided by operating activities									(1,029.1)	82.3	72.3
Investing activities:
Investment in subsidiaries									(135.0)		(164.0)
Proceeds from sale of business									4,118.3
Dividends received									922.6	810.1	360.6
Net cash provided by (used in) investing activities									4,905.9	810.1	196.6
Financing activities:
Borrowings under debt agreements									3,083.0	4,527.0	7,673.6
Repayments of borrowings									(5,778.2)	(4,838.3)	(7,232.4)
Payment of debt extinguishment costs									(46.1)
Payment of deferred financing costs									(20.7)	(4.6)	(33.7)
Purchase of treasury shares									(976.1)	(443.2)	(553.7)
Dividends paid									(127.4)	(125.2)	(115.5)
Proceeds from issuance of common stock									12.4	17.6	18.4
Other									(23.6)	(25.7)	(25.6)
Net cash (used in) provided by financing activities									(3,876.7)	(892.4)	(268.9)
Change in cash, cash equivalents and restricted cash									0.1
Cash, cash equivalents and restricted cash at beginning of year				$ 0.1				$ 0.1	0.1	0.1	0.1
Cash, cash equivalents and restricted cash at end of year	$ 0.2				$ 0.1				0.2	$ 0.1	$ 0.1
Non-cash investing items
Non-cash dividend									$ 3,000.0