Acquisitions (Acquired Finite-Lived Intangible Assets) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 42
Customer Lists
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 40
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