Stock-Based Compensation (Changes in Stock Appreciation Rights) (Details) - Stock Appreciation Rights (SARs) [Member] $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $	$ 9.2
Shares
Outstanding awards as of beginning of period (in shares) | shares	796,700,000
Granted (in shares) | shares	92,400,000
Exercised (in shares) | shares	(191,000,000.0)
Outstanding awards as of end of period (in shares) | shares	679,500,000
Exercisable at end of period (in shares) | shares	458,000,000.0
Weighted-Average Exercise Price per Share
Outstanding awards as of beginning of period (in usd per share) | $ / shares	$ 181.15
Granted (in usd per share) | $ / shares	278.00
Exercised (in usd per share) | $ / shares	130.35
Outstanding as of end of period (in shares) | $ / shares	205.41
Exercisable at end of period, Weighted-Average Exercise Price per Share (in usd per share) | $ / shares	$ 182.99
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period | shares	(18,600,000)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value | $ / shares	$ 225.82