The amount of net income or loss for the period in instances when the basic and diluted net income or loss available to common stockholders are the same amount and reported as a single line item on the face of the financial statements. Basic net income (loss) available to common stockholders is net income or loss after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period). Diluted net income (loss) available to common stockholders is net income or loss plus adjustments resulting from the assumption that dilutive convertible securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.

No definition available.

Earnings Per Common Share - Computation of EPS (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$ 30.5	$ 79.3	$ 180.7	$ 0.3	$ (4.4)	$ (7.5)	$ 123.7	$ 5.9	$ 290.8	$ 117.7	$ (64.9)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	2.1	1.0	10.9	48.9	(13.9)	(19.8)	(9.5)	1.1	62.9	(42.1)	10.2
Numerator:
Net income (loss)	$ 32.6	$ 80.3	$ 191.6	$ 49.2	$ (18.3)	$ (27.3)	$ 114.2	$ 7.0	353.7	75.6	(54.7)
Preferred stock dividends									10.4	10.4	10.4
Net Income (Loss) Available to Common Stockholders, Basic and Diluted									$ 343.3	$ 65.2	$ (65.1)
Weighted-average common shares outstanding - basic									209.6	208.5	205.9
Weighted Average Number of Shares Outstanding, Basic and Diluted											205.9
Denominator:
Stock-based compensation arrangements									0.6	1.1
Weighted Average Number of Shares Outstanding, Diluted									210.2	209.6	205.9
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.13	$ 0.37	$ 0.85	$ (0.01)	$ (0.03)	$ (0.05)	$ 0.58	$ 0.02	$ 1.34	$ 0.51	$ (0.37)
Earnings Per Share, Basic	0.14	0.37	0.90	0.22	(0.10)	(0.14)	0.54	0.02	1.64	0.31	(0.32)
Income (Loss) from Continuing Operations, Per Diluted Share	0.13	0.37	0.84	(0.01)	(0.03)	(0.05)	0.58	0.02	1.33	0.51	(0.37)
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0.01	0.00	0.05	0.23	(0.07)	(0.09)	(0.04)	0.00	0.30	(0.20)	0.05
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	0.01	0.00	0.05	0.23	(0.07)	(0.09)	(0.05)	0.00	0.30	(0.20)	0.05
Earnings Per Share, Diluted	$ 0.14	$ 0.37	$ 0.89	$ 0.22	$ (0.10)	$ (0.14)	$ 0.53	$ 0.02	$ 1.63	0.31	(0.32)
Earnings Per Share, Basic and Diluted										$ 0.31	$ (0.32)
Continuing Operations [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent									$ 290.8	$ 117.7	$ (64.9)
Numerator:
Preferred stock dividends									10.4	10.4	10.4
Net Income (Loss) Available to Common Stockholders, Basic and Diluted									280.4	$ 107.3	$ (75.3)
Denominator:
Earnings Per Share, Basic and Diluted										$ 0.51	$ (0.37)
Discontinued Operations [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent									62.9	$ (42.1)	$ 10.2
Numerator:
Preferred stock dividends									0.0	0.0	0.0
Net Income (Loss) Available to Common Stockholders, Basic and Diluted									$ 62.9	$ (42.1)	$ 10.2
Denominator:
Earnings Per Share, Basic and Diluted										$ (0.20)	$ 0.05