Share-Based Compensation - Outstanding and Exercisable Options Ranges (Details) $ / shares in Units, shares in Millions	12 Months Ended
Dec. 31, 2018 USD ($) $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number of Shares \| shares	6.2
Options Outstanding, Weighted Average Remaining Contractual Life	5 years 5 months
Options Outstanding, Weighted Average Exercise Price Per Share (usd per share)	$ 200.79
Options Outstanding, Aggregate Intrinsic Value \| $	$ 1,727,700,000
Options Exercisable, Number of Shares \| shares	5.0
Options Exercisable, Weighted Average Remaining Contractual Life	4 years 8 months
Options Exercisable, Weighted Average Exercise Price Per Share (usd per share)	$ 168.62
Options Exercisable, Aggregate Intrinsic Value \| $	$ 1,554,500,000
Closing stock price (usd per share) \| $	$ 478.92
Exercise Price Range 1
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum (usd per share)	$ 31.96
Range of Exercise Prices, maximum (usd per share)	$ 127.91
Options Outstanding, Number of Shares \| shares	1.4
Options Outstanding, Weighted Average Remaining Contractual Life	2 years 8 months
Options Outstanding, Weighted Average Exercise Price Per Share (usd per share)	$ 115.05
Options Exercisable, Number of Shares \| shares	1.4
Options Exercisable, Weighted Average Exercise Price Per Share (usd per share)	$ 115.05
Exercise Price Range 2
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum (usd per share)	128.30
Range of Exercise Prices, maximum (usd per share)	$ 168.41
Options Outstanding, Number of Shares \| shares	1.3
Options Outstanding, Weighted Average Remaining Contractual Life	4 years 7 months
Options Outstanding, Weighted Average Exercise Price Per Share (usd per share)	$ 156.67
Options Exercisable, Number of Shares \| shares	1.3
Options Exercisable, Weighted Average Exercise Price Per Share (usd per share)	$ 156.62
Exercise Price Range 3
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum (usd per share)	169.42
Range of Exercise Prices, maximum (usd per share)	$ 178.39
Options Outstanding, Number of Shares \| shares	1.4
Options Outstanding, Weighted Average Remaining Contractual Life	5 years 7 months
Options Outstanding, Weighted Average Exercise Price Per Share (usd per share)	$ 174.50
Options Exercisable, Number of Shares \| shares	1.2
Options Exercisable, Weighted Average Exercise Price Per Share (usd per share)	$ 174.17
Exercise Price Range 4
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum (usd per share)	178.75
Range of Exercise Prices, maximum (usd per share)	$ 283.51
Options Outstanding, Number of Shares \| shares	1.2
Options Outstanding, Weighted Average Remaining Contractual Life	6 years 2 months
Options Outstanding, Weighted Average Exercise Price Per Share (usd per share)	$ 214.60
Options Exercisable, Number of Shares \| shares	0.9
Options Exercisable, Weighted Average Exercise Price Per Share (usd per share)	$ 207.77
Exercise Price Range 5
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum (usd per share)	310.67
Range of Exercise Prices, maximum (usd per share)	$ 548.71
Options Outstanding, Number of Shares \| shares	0.9
Options Outstanding, Weighted Average Remaining Contractual Life	9 years 1 month
Options Outstanding, Weighted Average Exercise Price Per Share (usd per share)	$ 423.33
Options Exercisable, Number of Shares \| shares	0.2
Options Exercisable, Weighted Average Exercise Price Per Share (usd per share)	$ 388.12

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(iii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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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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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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