Stockholders' Equity - Schedule Of Stock Repurchase Activities (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Shares repurchased (shares)	0.6	0.0	7.3
Average price per share (usd per share)	$ 481.35	$ 0	$ 310.32
Value of shares repurchased	$ 269.5	$ 0.0	$ 2,274.0

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration