Share-based Compensation (Stock Award Activity, Options, SARs & PSARs) (Schedules) (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares
Options | Class A
Number of awards
Options outstanding at beginning of period (in shares) | shares	608,258
Options granted (in shares) | shares	59,672
Options expired, cancelled or forfeited (in shares) | shares	(45,753)
Options outstanding at end of period (in shares) | shares	622,177
Options exercisable and end of period (in shares) | shares	522,207
Weighted average exercise or base price
Options outstanding at beginning of period (in dollars per shares) | $ / shares	$ 30.02
Options granted (in dollars per shares) | $ / shares	17.22
Options expired, cancelled or forfeited (in dollars per shares) | $ / shares	28.89
Options outstanding at end of period (in dollars per shares) | $ / shares	28.87
Options exercisable at end of period (in dollars per share) | $ / shares	$ 30.60
Weighted average remaining contractual term
Options outstanding at end of period	3 years 6 months
Options exercisable at end of period	2 years 6 months
Aggregate intrinsic value
Options outstanding at end of period | $	$ 0.0
Options exercisable at end of period | $	$ 0.0
Options | Class C
Number of awards
Options outstanding at beginning of period (in shares) | shares	2,465,294
Options granted (in shares) | shares	386,050
Options expired, cancelled or forfeited (in shares) | shares	(146,961)
Options outstanding at end of period (in shares) | shares	2,704,383
Options exercisable and end of period (in shares) | shares	2,028,231
Weighted average exercise or base price
Options outstanding at beginning of period (in dollars per shares) | $ / shares	$ 25.84
Options granted (in dollars per shares) | $ / shares	19.02
Options expired, cancelled or forfeited (in dollars per shares) | $ / shares	27.22
Options outstanding at end of period (in dollars per shares) | $ / shares	24.79
Options exercisable at end of period (in dollars per share) | $ / shares	$ 25.76
Weighted average remaining contractual term
Options outstanding at end of period	5 years 2 months 12 days
Options exercisable at end of period	4 years
Aggregate intrinsic value
Options outstanding at end of period | $	$ 1.4
Options exercisable at end of period | $	$ 1.4
SARs | Class A
Number of awards
Options outstanding at beginning of period (in shares) | shares	21,183,640
Options granted (in shares) | shares	2,564,253
Options expired, cancelled or forfeited (in shares) | shares	(2,982,585)
Options exercised (in shares) | shares	(334,868)
Options outstanding at end of period (in shares) | shares	20,430,440
Options exercisable and end of period (in shares) | shares	15,176,348
Weighted average exercise or base price
Options outstanding at beginning of period (in dollars per shares) | $ / shares	$ 26.98
Options granted (in dollars per shares) | $ / shares	18.53
Options expired, cancelled or forfeited (in dollars per shares) | $ / shares	28.38
Options exercised (in dollars per share) | $ / shares	16.05
Options outstanding at end of period (in dollars per shares) | $ / shares	25.90
Options exercisable at end of period (in dollars per share) | $ / shares	$ 27.14
Weighted average remaining contractual term
Options outstanding at end of period	5 years 1 month 6 days
Options exercisable at end of period	3 years 10 months 24 days
Aggregate intrinsic value
Options outstanding at end of period | $	$ 5.5
Options exercisable at end of period | $	$ 5.5
SARs | Class C
Number of awards
Options outstanding at beginning of period (in shares) | shares	49,778,158
Options granted (in shares) | shares	6,632,778
Options expired, cancelled or forfeited (in shares) | shares	(8,166,202)
Options exercised (in shares) | shares	(710,018)
Options outstanding at end of period (in shares) | shares	47,534,716
Options exercisable and end of period (in shares) | shares	32,831,063
Weighted average exercise or base price
Options outstanding at beginning of period (in dollars per shares) | $ / shares	$ 26.20
Options granted (in dollars per shares) | $ / shares	19.39
Options expired, cancelled or forfeited (in dollars per shares) | $ / shares	27.03
Options exercised (in dollars per share) | $ / shares	15.12
Options outstanding at end of period (in dollars per shares) | $ / shares	25.28
Options exercisable at end of period (in dollars per share) | $ / shares	$ 26.32
Weighted average remaining contractual term
Options outstanding at end of period	5 years 6 months
Options exercisable at end of period	4 years 2 months 12 days
Aggregate intrinsic value
Options outstanding at end of period | $	$ 22.1
Options exercisable at end of period | $	$ 22.1
PSARs | Class A
Number of awards
Options outstanding at beginning of period (in shares) | shares	3,281,811
Options expired, cancelled or forfeited (in shares) | shares	(43,451)
Options outstanding at end of period (in shares) | shares	3,238,360
Options exercisable and end of period (in shares) | shares	3,238,360
Weighted average exercise or base price
Options outstanding at beginning of period (in dollars per shares) | $ / shares	$ 25.97
Options expired, cancelled or forfeited (in dollars per shares) | $ / shares	25.97
Options outstanding at end of period (in dollars per shares) | $ / shares	25.97
Options exercisable at end of period (in dollars per share) | $ / shares	$ 25.97
Weighted average remaining contractual term
Options outstanding at end of period	5 years 2 months 12 days
Options exercisable at end of period	5 years 2 months 12 days
Aggregate intrinsic value
Options outstanding at end of period | $	$ 0.0
Options exercisable at end of period | $	$ 0.0
PSARs | Class C
Number of awards
Options outstanding at beginning of period (in shares) | shares	6,417,033
Options expired, cancelled or forfeited (in shares) | shares	(81,960)
Options outstanding at end of period (in shares) | shares	6,335,073
Options exercisable and end of period (in shares) | shares	6,335,073
Weighted average exercise or base price
Options outstanding at beginning of period (in dollars per shares) | $ / shares	$ 25.22
Options expired, cancelled or forfeited (in dollars per shares) | $ / shares	25.22
Options outstanding at end of period (in dollars per shares) | $ / shares	25.22
Options exercisable at end of period (in dollars per share) | $ / shares	$ 25.22
Weighted average remaining contractual term
Options outstanding at end of period	5 years 2 months 12 days
Options exercisable at end of period	5 years 2 months 12 days
Aggregate intrinsic value
Options outstanding at end of period | $	$ 0.0
Options exercisable at end of period | $	$ 0.0
Options, SARs and PSARs | Class A | Former Employees
Number of awards
Options outstanding at end of period (in shares) | shares	1,122,607
Options exercisable and end of period (in shares) | shares	1,090,530
Weighted average exercise or base price
Options outstanding at end of period (in dollars per shares) | $ / shares	$ 32.54
Options exercisable at end of period (in dollars per share) | $ / shares	$ 32.81
Weighted average remaining contractual term
Options outstanding at end of period	2 years 4 months 24 days
Options exercisable at end of period	2 years 2 months 12 days
Aggregate intrinsic value
Options outstanding at end of period | $	$ 0.1
Options exercisable at end of period | $	$ 0.1
Options, SARs and PSARs | Class C | Former Employees
Number of awards
Options outstanding at end of period (in shares) | shares	2,221,159
Options exercisable and end of period (in shares) | shares	2,157,015
Weighted average exercise or base price
Options outstanding at end of period (in dollars per shares) | $ / shares	$ 31.64
Options exercisable at end of period (in dollars per share) | $ / shares	$ 31.88
Weighted average remaining contractual term
Options outstanding at end of period	3 years
Options exercisable at end of period	2 years 10 months 24 days
Aggregate intrinsic value
Options outstanding at end of period | $	$ 0.2
Options exercisable at end of period | $	$ 0.2