Revenue - Revenue Disclosure (Details)	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Customer Contract, Lower Range, in Years	1
Customer Contract, Upper Range, in Years	5
Payment terms for customers, lower range	30
Payment term for customers, upper range	180
Indefeasible Right of Use, Lower Range, in Years	15
Indefeasible Right of Use, Upper Range, in Years	25