Stock-Based Compensation (Unrecognized Stock-Based Compensation Expense) (Details) $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit related to the stock-based compensation expense	$ 45.7
Expected amortization period (months)	32 months
Restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit related to the stock-based compensation expense	$ 38.8
Expected amortization period (months)	33 months
Market Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit related to the stock-based compensation expense	$ 6.9
Expected amortization period (months)	26 months

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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