v3.8.0.1

Fair Value Measurements (Tables) | 12 Months Ended
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Dec. 31, 2017
Fair Value Disclosures [Abstract] |
Fair Value, Liabilities Measured on Recurring Basis | 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, 2017 |  |  |  |  |  |  |
Deferred compensation liabilities | — |  |  | $ | 20.9 |  |  | — |  |  | $ | 20.9 |
December 31, 2016 |  |  |  |  |  |  |
Deferred compensation liabilities | — |  |  | $ | 14.8 |  |  | — |  |  | $ | 14.8 |
Carrying Values and Fair Values of Financial Instruments | The carrying amounts and fair values of financial instruments as of December 31 were as follows ($ in millions):
| 2017 |  | 2016
| Carrying Amount |  | Fair Value |  | Carrying Amount |  | Fair Value
Long-term borrowings | $ | 4,056.2 |  |  | $ | 4,051.8 |  |  | $ | 3,358.0 |  |  | $ | 3,321.4 |

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- Definition Tabular disclosure of liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). Where the quoted price in an active market for the identical liability is not available, the Level 1 input is the quoted price of an identical liability when traded as an asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19190-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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- Definition Tabular disclosure of information pertaining to carrying amount and estimated fair value of short-term and long-term debt instruments or arrangements, including but not limited to, identification of terms, features, and collateral requirements. + References No definition available. + Details
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