Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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- Definition

Aggregate dividends paid during the period for each share of common stock outstanding.

+ References

+ Details

Name:	us-gaap_CommonStockDividendsPerShareCashPaid
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Period Type:	duration

- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

+ Details

Name:	us-gaap_CommonStockDividendsPerShareDeclared
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- Definition

Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared, for example, but not limited to, common and preferred stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 405
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6957935&loc=d3e64057-112817

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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Stockholders' (Deficit) Equity - Schedule of Dividends Declared (Details) - USD ($) $ / shares in Units, $ in Millions																			3 Months Ended								6 Months Ended	9 Months Ended	12 Months Ended
	Feb. 20, 2019	Jan. 04, 2019	Oct. 06, 2018	Oct. 05, 2018	Aug. 02, 2018	Jul. 06, 2018	May 14, 2018	Apr. 06, 2018	Feb. 14, 2018	Jan. 05, 2018	Oct. 06, 2017	Aug. 10, 2017	Jul. 07, 2017	May 15, 2017	Apr. 07, 2017	Feb. 22, 2017	Jan. 06, 2017	Jan. 08, 2016	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Dividends declared per common share (USD per share)			$ 0.63		$ 0.63		$ 0.63		$ 0.63		$ 0.97	$ 0.97		$ 0.97		$ 0.97						$ 0.97		$ 0.92	$ 0.92				$ 2.52	$ 3.88	$ 3.73
Dividends paid per common share (USD per share)				$ 0.63		$ 0.63		$ 0.63		$ 0.97	$ 0.970		$ 0.970		$ 0.970		$ 0.970	$ 0.92						$ 0.92	$ 0.92	$ 0.92			$ 2.86	$ 3.88	$ 3.68
Payments of dividends										$ 17.7							$ 17.5	$ 17.1	$ 11.4	$ 11.4	$ 11.5		$ 17.5	$ 16.7	$ 16.8	$ 17.0	$ 17.5	$ 17.8	$ 52.0	$ 70.3	$ 67.6
Subsequent Event
Class of Stock [Line Items]
Dividends paid per common share (USD per share)	$ 0.69
Payments of dividends		$ 11.4