Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Other intangible assets	$ 5,811	$ 6,063
Intangible assets subject to amortization	2,846	3,114
Intangible assets not subject to amortization	2,965	2,949
Amortization of Purchased Intangibles	$ 290	$ 305	$ 339