Capital Stock, Accumulated Other Comprehensive Loss and Equity - Quarterly Dividend (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Dividends declared	$ 62.1	$ 186.3	$ 185.8
Dividends paid	$ 67.3	$ 186.3	$ 186.3

Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration