Shareholders' Equity Cash Dividend Restrictions (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
C Cash Dividend Restrictions [Abstract]
Amount available for dividend distribution without prior approval from regulatory agency	$ 699.3
Dividends declared to the Company by it subsidiaries	$ 472.4	$ 399.5	$ 412.3

Amount of dividends that can be declared or paid without approval of regulatory agency.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant