Accumulated Other Comprehensive Loss (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Capital Stock [Abstract]
Adoption of ASU 2018-02	$ (725.1)	$ (694.0)	$ (678.1)

The cumulative amount of the reporting entity's undistributed earnings or deficit.

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