Long-Term Debt Debt Extinguishment Costs (Details)	12 Months Ended
Dec. 31, 2017
Extinguishment of Debt [Line Items]
Schedule of Debt Extinguishment Costs [Table Text Block]	During 2017, we had no debt extinguishment costs, compared with less than $1 million in 2016 and $3 million in 2015.

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Balance Type:	na
Period Type:	duration