Supplemental Guarantor Information HY Condensed Consolidating Statements of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ 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	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Revenue, Net	$ 285.3	$ 312.4	$ 299.2	$ 288.9	$ 289.3	$ 299.8	$ 285.8	$ 292.9	$ 1,185.8	$ 1,167.8	$ 1,161.5
Costs and Expenses									1,092.8	1,039.8	984.6
Operating Income (Loss)	10.5	25.5	27.4	29.6	25.0	36.2	29.7	37.1	93.0	128.0	176.9
Other Nonoperating Income (Expense)									7.6	(2.6)	(5.1)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest									162.9	450.6	199.1
Income tax expense (benefit)									61.1	159.8	81.4
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	(1.6)	18.8	77.6	7.0	30.5	79.3	180.7	0.3	101.8	290.8	117.7
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0.3	0.0	0.0	0.0	2.1	1.0	10.9	48.9	0.3	62.9	(42.1)
Net Income (Loss) Attributable to Parent	$ (1.3)	$ 18.8	$ 77.6	$ 7.0	$ 32.6	$ 80.3	$ 191.6	$ 49.2	102.1	353.7	75.6
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									80.7	2.9	(40.6)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									182.8	356.6	35.0
Preferred Stock Dividends, Income Statement Impact									10.4	10.4	10.4
Net Income (Loss) Available to Common Stockholders, Basic									91.7	343.3	65.2
Notes guaranteed by subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue, Net									1,185.8	1,167.8	1,161.5
Costs and Expenses									1,092.8	1,039.8	984.6
Operating Income (Loss)									93.0	128.0	176.9
Interest Income (Expense), Net									75.7	103.1	145.9
Other Nonoperating Income (Expense)									(145.6)	(425.7)	(168.1)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest									162.9	450.6	199.1
Income tax expense (benefit)									61.1	159.8	81.4
Equity in earnings of subsidiaries, net of tax									0.0	0.0	0.0
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									101.8	290.8	117.7
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent									0.3	62.9	(42.1)
Net Income (Loss) Attributable to Parent									102.1	353.7	75.6
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									80.7	2.9	(40.6)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									182.8	356.6	35.0
Preferred Stock Dividends, Income Statement Impact									10.4	10.4	10.4
Net Income (Loss) Available to Common Stockholders, Basic									91.7	343.3	65.2
Notes guaranteed by subsidiaries [Member] | Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue, Net									(39.8)	(38.6)	(39.1)
Costs and Expenses									(39.8)	(38.6)	(39.1)
Operating Income (Loss)									0.0	0.0	0.0
Interest Income (Expense), Net									0.0	0.0	0.0
Other Nonoperating Income (Expense)									0.0	0.0	0.0
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest									0.0	0.0	0.0
Income tax expense (benefit)									0.0	0.0	0.0
Equity in earnings of subsidiaries, net of tax									(191.0)	(455.0)	(201.5)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									(191.0)	(455.0)	(201.5)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent									0.0	0.0	0.0
Net Income (Loss) Attributable to Parent									(191.0)	(455.0)	(201.5)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									0.0	0.0	0.0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									(191.0)	(455.0)	(201.5)
Preferred Stock Dividends, Income Statement Impact									0.0	0.0	0.0
Net Income (Loss) Available to Common Stockholders, Basic									(191.0)	(455.0)	(201.5)
Notes guaranteed by subsidiaries [Member] | Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue, Net									0.0	0.0	0.0
Costs and Expenses									20.7	22.4	21.5
Operating Income (Loss)									(20.7)	(22.4)	(21.5)
Interest Income (Expense), Net									94.4	112.7	142.6
Other Nonoperating Income (Expense)									20.3	19.5	17.6
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest									(135.4)	(154.6)	(181.7)
Income tax expense (benefit)									(46.5)	(53.3)	(55.8)
Equity in earnings of subsidiaries, net of tax									191.0	455.0	201.5
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									102.1	353.7	75.6
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent									0.0	0.0	0.0
Net Income (Loss) Attributable to Parent									102.1	353.7	75.6
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									12.7	3.3	(40.5)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									114.8	357.0	35.1
Preferred Stock Dividends, Income Statement Impact									10.4	10.4	10.4
Net Income (Loss) Available to Common Stockholders, Basic									91.7	343.3	65.2
Notes guaranteed by subsidiaries [Member] | Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue, Net									539.0	532.4	532.0
Costs and Expenses									510.7	503.9	505.4
Operating Income (Loss)									28.3	28.5	26.6
Interest Income (Expense), Net									(25.2)	(10.2)	6.2
Other Nonoperating Income (Expense)									(150.4)	(432.9)	(171.6)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest									203.9	471.6	192.0
Income tax expense (benefit)									74.0	165.5	68.3
Equity in earnings of subsidiaries, net of tax									0.0	0.0	0.0
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									129.9	306.1	123.7
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent									0.3	62.9	(42.1)
Net Income (Loss) Attributable to Parent									130.2	369.0	81.6
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									68.1	0.0	(0.1)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									198.3	369.0	81.5
Preferred Stock Dividends, Income Statement Impact									0.0	0.0	0.0
Net Income (Loss) Available to Common Stockholders, Basic									130.2	369.0	81.6
Notes guaranteed by subsidiaries [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue, Net									686.6	674.0	668.6
Costs and Expenses									601.2	552.1	496.8
Operating Income (Loss)									85.4	121.9	171.8
Interest Income (Expense), Net									6.5	0.6	(2.9)
Other Nonoperating Income (Expense)									(15.5)	(12.3)	(14.1)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest									94.4	133.6	188.8
Income tax expense (benefit)									33.6	47.6	68.9
Equity in earnings of subsidiaries, net of tax									0.0	0.0	0.0
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									60.8	86.0	119.9
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent									0.0	0.0	0.0
Net Income (Loss) Attributable to Parent									60.8	86.0	119.9
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									(0.1)	(0.4)	0.0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									60.7	85.6	119.9
Preferred Stock Dividends, Income Statement Impact									0.0	0.0	0.0
Net Income (Loss) Available to Common Stockholders, Basic									$ 60.8	$ 86.0	$ 119.9