Summary of Significant Accounting Policies (Cash Flow, Supplemental Disclosures) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Increase (Decrease) in Restricted Cash		$ 0.0
Net Cash Provided by (Used in) Investing Activities	$ (460.3)	(274.4)
Net increase in cash, cash equivalents, restricted cash and restricted cash equivalents	116.2	88.5
Cash, cash equivalents, restricted cash and restricted cash equivalents beginning of period	263.8	239.3
Cash, cash equivalents, restricted cash and restricted cash equivalents end of period	$ 380.0	327.8
Restatement Adjustment [Member]
Increase (Decrease) in Restricted Cash		92.0
Net Cash Provided by (Used in) Investing Activities		92.0
Net increase in cash, cash equivalents, restricted cash and restricted cash equivalents		92.0
Cash, cash equivalents, restricted cash and restricted cash equivalents beginning of period		224.7
Cash, cash equivalents, restricted cash and restricted cash equivalents end of period		316.7
Scenario, Previously Reported [Member]
Increase (Decrease) in Restricted Cash		(92.0)
Net Cash Provided by (Used in) Investing Activities		(366.4)
Net increase in cash, cash equivalents, restricted cash and restricted cash equivalents		(3.5)
Cash, cash equivalents, restricted cash and restricted cash equivalents beginning of period		14.6
Cash, cash equivalents, restricted cash and restricted cash equivalents end of period		$ 11.1

Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3521-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 50
-Paragraph 8
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Amount of increase (decrease) in cash, cash equivalents, and cash and cash equivalents restricted to withdrawal or usage; including effect from exchange rate change. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 230
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The net cash inflow or outflow for the increase (decrease) associated with funds that are not available for withdrawal or use (such as funds held in escrow) and are associated with underlying transactions that are classified as investing activities.

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Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

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