Share-Based Payments - Performance Stock Units Settled in Stock Activity (Details) - Performance stock units settled in stock shares in Thousands	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Shares
Beginning balance, unvested shares (in shares) | shares	111,000
Granted (in shares) | shares	73,000	[1]
Vested (in shares) | shares	0
Forfeited (in shares) | shares	(29,000)
Ending balance, unvested shares (in shares) | shares	155,000
Weighted Average Grant Date Fair Value
Beginning balance, weighted average grant date fair value (in dollars per share) | $ / shares	$ 316.39
Granted (in dollars per share) | $ / shares	293.35	[1]
Vested (in dollars per share) | $ / shares	0
Forfeited (in dollars per share) | $ / shares	323.42
Ending balance, weighted average grant date fair value (in dollars per share) | $ / shares	$ 304.19

[1] PSUs settled in stock granted in 2020 include awards granted in conjunction with our annual awards made in February 2020 and PSUs granted in conjunction with the hiring of employees. These grants reflect the target number of shares eligible to be earned at the time of grant.