Share-Based Compensation (Summary of Stock Option Activity) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Number of Stock Options
Outstanding at beginning of period (in shares)	268,817
Granted (in shares)	204,624
Outstanding at end of period (in shares)	473,441	268,817
Exercisable (in shares)	268,817		300,000
Weighted-Average Exercise Price
Weighted average exercise price, outstanding, beginning of period (in dollars per share)	$ 66.68
Granted (in dollars per share)	202.46
Weighted average exercise price, outstanding, end of period (in dollars per share)	125.36	$ 66.68
Options exercisable, weighted average exercise price (in dollars per share)	$ 66.68		$ 66.68
Weighted-average remaining contractual term, Outstanding (in years)	6 years 10 months 24 days	5 years
Weighted-average remaining contractual term, Exercisable (in years)	4 years 9 months 18 days
Aggregate Intrinsic Value (in millions)	$ 30	$ 39
Aggregate Intrinsic Value, exercisable (in millions)	$ 30

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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Gross 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 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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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 remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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