Share-Based Compensation - Assumptions for Valuation of RSUs (Details) - Market-Based Restricted Stock Units	Mar. 15, 2019	Mar. 08, 2019	Oct. 01, 2018	Jul. 01, 2018	May 30, 2018	Apr. 22, 2018	Apr. 02, 2018	Feb. 26, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Stock Price Volatility	22.00%	22.00%	25.00%	30.00%	22.00%	22.00%	30.00%	30.00%
Risk-Free Interest Rate	2.40%	2.43%	2.85%	2.58%	2.40%	2.40%	2.34%	2.35%
Dividend Yield	2.62%	2.70%	3.01%	3.41%	2.62%	2.62%	4.04%	4.70%

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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 (f)(2)(iii)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

+ References

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 (f)(2)(ii)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

+ References

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 (f)(2)(iv)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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