Acquisitions (Acquired Finite-Lived Intangible Assets) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2016 USD ($)
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 43
Customer Lists
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 41
Finite-lived intangible assets, remaining amortization period	10 years
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 2
Finite-lived intangible assets, remaining amortization period	3 years