Goodwill And Acquired Intangibles (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Carrying amount of indefinite-lived intangible assets relating to trade names	$ 490	$ 490
Amortization expense of acquired finite-lived intangible assets	240	220
Finite-lived Intangible Assets Acquired	298	113
Non-cash investing and financing transactions related to acquired finite-lived intangibles	$ 55	$ 31