Stock-Based Incentive Compensation Plans (Summary of activity for restricted stock units) (Details) - Restricted Stock Units [Member]	12 Months Ended
	Dec. 31, 2019 $ / shares shares
Shares:
Outstanding as of beginning of year (in shares) | shares	1,692,876
Granted (in shares) | shares	621,134
Vested (in shares) | shares	(680,494)
Forfeited (in shares) | shares	(82,387)
Outstanding as of end of year (in shares) | shares	1,551,129
Weighted-Average Grant Date Fair Value
Weighted-average grant date fair value, outstanding as of beginning of year (in dollars per share) | $ / shares	$ 60.02
Weighted-average grant date fair value, granted (in dollars per share) | $ / shares	62.88
Weighted-average grant date fair value, vested (in dollars per share) | $ / shares	38.40
Weighted-average grant date fair value, forfeited (in dollars per share) | $ / shares	70.51
Weighted-average grant date fair value, outstanding as of end of year (in dollars per share) | $ / shares	$ 70.09