Share-based Compensation (Stock Award Activity, Options, SARs & PSARs) (Schedules) (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) $ / shares shares
Options | Class A
Number of shares
Options outstanding at beginning of period (in shares) | shares	580,481
Options granted (in shares) | shares	71,469
Options expired, cancelled or forfeited (in shares) | shares	(1,713)
Options exercised (in dollars per share) | shares	(69,983)
Options outstanding at end of period (in shares) | shares	580,254
Options exercisable and end of period (in shares) | shares	417,608
Weighted average exercise price
Options outstanding at beginning of period (in dollars per shares) | $ / shares	$ 25.54
Options granted (in dollars per shares) | $ / shares	30.14
Options expired, cancelled or forfeited (in dollars per shares) | $ / shares	22.43
Options exercised (in dollars per share) | $ / shares	13.97
Options outstanding at end of period (in dollars per shares) | $ / shares	27.51
Options exercisable at end of period (in dollars per share) | $ / shares	$ 26.26
Weighted average remaining contractual term, in years
Options outstanding at end of period	3 years 8 months 12 days
Options exercisable at end of period	2 years 10 months 24 days
Aggregate intrinsic value
Options outstanding at end of period | $	$ 1.4
Options exercisable at end of period | $	$ 1.4
Options | Class C
Number of shares
Options outstanding at beginning of period (in shares) | shares	2,725,566
Options granted (in shares) | shares	770,691
Options expired, cancelled or forfeited (in shares) | shares	(591,662)
Options exercised (in dollars per share) | shares	(237,089)
Options outstanding at end of period (in shares) | shares	2,667,506
Options exercisable and end of period (in shares) | shares	2,161,408
Weighted average exercise price
Options outstanding at beginning of period (in dollars per shares) | $ / shares	$ 25.58
Options granted (in dollars per shares) | $ / shares	24.82
Options expired, cancelled or forfeited (in dollars per shares) | $ / shares	30.07
Options exercised (in dollars per share) | $ / shares	17.49
Options outstanding at end of period (in dollars per shares) | $ / shares	25.09
Options exercisable at end of period (in dollars per share) | $ / shares	$ 24.16
Weighted average remaining contractual term, in years
Options outstanding at end of period	2 years 10 months 24 days
Options exercisable at end of period	2 years 3 months 18 days
Aggregate intrinsic value
Options outstanding at end of period | $	$ 3.9
Options exercisable at end of period | $	$ 3.9
SARs and PSARs | Class A
Number of shares
Options outstanding at beginning of period (in shares) | shares	13,524,075
Options granted (in shares) | shares	3,286,731
Options expired, cancelled or forfeited (in shares) | shares	(898,390)
Options exercised (in dollars per share) | shares	(603,854)
Options outstanding at end of period (in shares) | shares	15,308,562
Options exercisable and end of period (in shares) | shares	9,837,206
Weighted average exercise price
Options outstanding at beginning of period (in dollars per shares) | $ / shares	$ 32.72
Options granted (in dollars per shares) | $ / shares	29.81
Options expired, cancelled or forfeited (in dollars per shares) | $ / shares	34.77
Options exercised (in dollars per share) | $ / shares	21.75
Options outstanding at end of period (in dollars per shares) | $ / shares	32.41
Options exercisable at end of period (in dollars per share) | $ / shares	$ 32.38
Weighted average remaining contractual term, in years
Options outstanding at end of period	3 years 8 months 12 days
Options exercisable at end of period	2 years 8 months 12 days
Aggregate intrinsic value
Options outstanding at end of period | $	$ 0.7
Options exercisable at end of period | $	$ 0.7
SARs | Class C
Number of shares
Options outstanding at beginning of period (in shares) | shares	31,305,136
Options granted (in shares) | shares	6,573,462
Options expired, cancelled or forfeited (in shares) | shares	(1,797,629)
Options exercised (in dollars per share) | shares	(1,678,989)
Options outstanding at end of period (in shares) | shares	34,401,980
Options exercisable and end of period (in shares) | shares	23,452,476
Weighted average exercise price
Options outstanding at beginning of period (in dollars per shares) | $ / shares	$ 30.60
Options granted (in dollars per shares) | $ / shares	28.86
Options expired, cancelled or forfeited (in dollars per shares) | $ / shares	33.54
Options exercised (in dollars per share) | $ / shares	20.35
Options outstanding at end of period (in dollars per shares) | $ / shares	30.61
Options exercisable at end of period (in dollars per share) | $ / shares	$ 30.21
Weighted average remaining contractual term, in years
Options outstanding at end of period	3 years 6 months
Options exercisable at end of period	2 years 4 months 24 days
Aggregate intrinsic value
Options outstanding at end of period | $	$ 2.2
Options exercisable at end of period | $	$ 2.2
Options and SARs | Class A | Former Employees
Number of shares
Options outstanding at end of period (in shares) | shares	1,198,985
Options exercisable and end of period (in shares) | shares	1,017,362
Weighted average exercise price
Options outstanding at end of period (in dollars per shares) | $ / shares	$ 32.74
Options exercisable at end of period (in dollars per share) | $ / shares	$ 32.26
Weighted average remaining contractual term, in years
Options outstanding at end of period	2 years 10 months 24 days
Options exercisable at end of period	2 years 7 months 6 days
Aggregate intrinsic value
Options outstanding at end of period | $	$ 0.1
Options exercisable at end of period | $	$ 0.1
Options and SARs | Class C | Former Employees
Number of shares
Options outstanding at end of period (in shares) | shares	2,819,203
Options exercisable and end of period (in shares) | shares	2,455,257
Weighted average exercise price
Options outstanding at end of period (in dollars per shares) | $ / shares	$ 30.54
Options exercisable at end of period (in dollars per share) | $ / shares	$ 29.98
Weighted average remaining contractual term, in years
Options outstanding at end of period	2 years 8 months 12 days
Options exercisable at end of period	2 years 4 months 24 days
Aggregate intrinsic value
Options outstanding at end of period | $	$ 0.3
Options exercisable at end of period | $	$ 0.3