Share-Based Compensation (Stock Option Activity) (Details) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at the beginning of the period | shares	35
Granted | shares	7
Exercised | shares	(9)
Forfeitures | shares	(1)
Outstanding at the end of the period | shares	32
Exercisable at end of period | shares	15
Vested and expected to vest, end of period | shares	31
Outstanding at beginning of period, Weighted-Average Exercise Price | $ / shares	$ 131
Granted, Weighted-Average Exercise Price | $ / shares	260
Exercised, Weighted-Average Exercise Price | $ / shares	94
Forfeitures, Weighted Average Exercise Price | $ / shares	212
Outstanding at end of period, Weighted-Average Exercise Price | $ / shares	166
Exercisable at end of period, Weighted-Average Exercise Price | $ / shares	114
Vested and expected to vest end of period, Weighted-Average Exercise Price | $ / shares	$ 165
Outstanding at end of period, Weighted Average Remaining Contractual Term (in years)	6 years 6 months
Exercisable at end of period, Weighted Average Remaining Contractual Term (in years)	5 years
Vested and expected to vest end of period, Weighted Average Remaining Contractual Term (in years)	6 years 4 months 24 days
Outstanding at end of period, Aggregate Intrinsic Value | $	$ 4,106
Exercisable at end of period, Aggregate Intrinsic Value | $	2,716
Vested and expected to vest end of period, Aggregate Intrinsic Value | $	$ 4,068