Stock-Based Compensation (Performance Share Awards Activity) (Details) - Performance Shares	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Performance Shares (in shares):
Balance at beginning of period (in shares) | shares	1,554,697
Grants (in shares) | shares	467,288
Forfeitures (in shares) | shares	(47,067)
Payouts (in shares) | shares	(532,700)
Balance at end of period (in shares) | shares	1,442,218
Weighted Average Grant Date Fair Value (in dollars per share):
Balance at beginning of period (in dollars per share) | $ / shares	$ 69.32
Grants (in dollars per share) | $ / shares	83.85
Forfeitures (in dollars per share) | $ / shares	76.22
Payouts (in dollars per share) | $ / shares	0.00
Balance at end of period (in dollars per share) | $ / shares	$ 75.85