Acquisitions / Dispositions (Acquired Finite-Lived Intangibles Assets) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 486
Customer Lists
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 433
Finite-lived intangible assets, remaining amortization period	13 years
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 53
Finite-lived intangible assets, remaining amortization period	4 years 9 months 18 days