Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 15,271	$ 15,541	$ 15,332
Other intangible assets	6,100	6,500
Intangible assets subject to amortization	3,200	3,500
Intangible assets not subject to amortization	2,900	3,000
Amortization of Purchased Intangibles	$ 339	$ 260	$ 19