Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation Expense

Stock-based compensation expense is as follows (in millions):

	Year Ended December 31,
	2021		2022		2023
Cost of sales	$	540	$	757	$	836
Fulfillment	1,946		2,745		3,090
Technology and infrastructure	6,645		10,621		13,434
Sales and marketing	2,530		3,875		4,623
General and administrative	1,096		1,623		2,040
Total stock-based compensation expense (1)	$	12,757	$	19,621	$	24,023

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(1)The related tax benefits were $2.7 billion, $4.3 billion, and $5.4 billion for 2021, 2022, and 2023.

Summary of Restricted Stock Unit Activity

The following table summarizes our restricted stock unit activity (in millions):

	Number of Units	Weighted Average Grant-Date Fair Value
Outstanding as of January 1, 2021	303.3	$	100
Units granted	127.3	167
Units vested	(108.4)	85
Units forfeited	(42.3)	116
Outstanding as of December 31, 2021	279.9	134
Units granted	262.8	142
Units vested	(113.3)	114
Units forfeited	(45.0)	143
Outstanding as of December 31, 2022	384.4	144
Units granted	218.1	106
Units vested	(139.9)	143
Units forfeited	(56.8)	135
Outstanding as of December 31, 2023	405.8	125

Scheduled Vesting of Outstanding Restricted Stock Units

Scheduled vesting for outstanding restricted stock units as of December 31, 2023, is as follows (in millions):

	Year Ended
	2024	2025	2026	2027	2028	Thereafter	Total
Scheduled vesting — restricted stock units	218.3	124.6	48.7	11.2	1.3	1.7	405.8