Fair Value Measurements (Major Categories of Financial Assets and Liabilities Measured on a Recurring Basis) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Short-term investments	$ 28
Other current assets	288	$ 435
Other assets	323	464
Other accrued liabilities	59	88
Other liabilities	565	282
Fair Value, Inputs, Level 2 [Member]
Short-term investments	28
Other current assets	288	435
Other assets	31	175
Other accrued liabilities	56	88
Other liabilities	545	282
Fair Value, Inputs, Level 3 [Member]
Other assets	292	$ 289
Other accrued liabilities	3
Other liabilities	20
Contingent consideration	$ 23