Income Taxes (Schedule of Unrecognized Tax Benefits Roll Forward) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits – January 1	$ 2,412	$ 1,736	$ 1,557
Gross increases – tax positions in prior periods	100	87	3
Gross decreases – tax positions in prior periods	(1,418)	(410)	(44)
Gross increases – current-period tax positions	344	1,208	220
Gross decreases - current period tax positions	(1)
Settlements	39	206
Statute Lapse		3
Unrecognized tax benefits – December 31	$ 1,476	$ 2,412	$ 1,736