Equity Based Compensation (Disclosure of Share-based Compensation Arrangements by Share-based Payment Award) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options, Grants in Period, Weighted Average Exercise Price	$ 150.87	$ 129.72	$ 93.53
Options, Outstanding, Intrinsic Value	$ 126.7
Options, Exercisable, Intrinsic Value	$ 110.1
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, Number, Beginning Balance	2,309,769,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	164,889,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	(286,874,000)
Forfeited	(17,341,000)
Outstanding, Number, Ending Balance	2,170,443,000	2,309,769,000
Options exercisable	1,633,182,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options, Outstanding, Weighted Average Exercise Price, Beginning of Period	$ 75.17
Options, Grants in Period, Weighted Average Exercise Price	150.87
Exercised / Lapsed	59.45
Forfeited	119.63
Options, Outstanding, Weighted Average Exercise Price, End of Period	82.65	$ 75.17
Options exercisable	$ 73.09

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Net number of share options (or share units) granted during the period.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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