Acquisitions / Dispositions (Acquired Finite-Lived Intangibles Assets) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 307
Customer Lists
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 241
Finite-lived intangible assets, remaining amortization period	13 years
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 66	[1]
Finite-lived intangible assets, remaining amortization period	7 years	[1]

[1] Primarily non-compete agreements, trade names and developed technology