Stock-Based Compensation Plans - Summary of Stock Options Activity (Details) - Amended and Restated 2004 Stock Incentive Plan $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($) $ / shares shares
Shares Subject to Options (in shares)
Outstanding as of beginning of the period \| shares	3,456
Granted \| shares	0
Exercised \| shares	(271)
Forfeited \| shares	0
Expired \| shares	0
Outstanding as of end of the period \| shares	3,185
Exercisable as of end of the period \| shares	3,034
Weighted- Average Exercise Price (in dollars per share)
Outstanding as of beginning of the period \| $ / shares	$ 56.03
Granted \| $ / shares	0.00
Exercised \| $ / shares	61.83
Forfeited \| $ / shares	0.00
Expired \| $ / shares	0.00
Outstanding as of end of the period \| $ / shares	55.54
Exercisable as of end of the period \| $ / shares	$ 54.01
Weighted-Average Remaining Contractual Term, Outstanding at end of period, years	2 years 9 months 21 days
Weighted-Average Remaining contractual Term Exercisable, at end of period years	2 years 7 months 6 days
Aggregate Intrinsic Value, Outstanding, at end of period \| $	$ 151
Aggregate Intrinsic Value, Exercisable, at end of period \| $	$ 148

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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Balance Type:	na
Period Type:	instant

- Definition

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.