Fair Value Measurements (Gains/Losses Included In Earnings Relating to Assets Still Held at the End of Period) (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in unrealized gain (loss)	$ 45	$ 21	$ 33
Derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in unrealized gain (loss)	32	(7)	0
Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in unrealized gain (loss)	$ 13	$ 28	$ 33