Fair Value Measurements (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2017

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Fair Value, Liabilities Measured on Recurring Basis

A summary of financial liabilities that are measured at fair value on a recurring basis were as follows ($ in millions):

	Quoted Prices in Active Market (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
March 31, 2017
Deferred compensation liabilities	$	—	$	17.9	$	—	$	17.9
December 31, 2016
Deferred compensation liabilities	$	—	$	14.8	$	—	$	14.8

Financial liabilities that are measured at fair value on a recurring basis were as follows ($ in millions):

	Quoted Prices in Active Market (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
December 31, 2016
Deferred compensation liabilities		—	$	14.8		—	$	14.8
December 31, 2015
Deferred compensation liabilities		—	$	53.7		—	$	53.7

Carrying Amounts and Fair Values of Financial Instruments

The carrying amounts and fair values of financial instruments were as follows ($ in millions):

	March 31, 2017				December 31, 2016
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Long-term borrowings	$	3,262.7	$	3,240.5	$	3,358.0	$	3,321.4

The carrying amounts and fair values of financial instruments were as follows ($ in millions):

	December 31, 2016
	Carrying Amount		Fair Value
Long-term borrowings	$	3,358.0	$	3,321.4