Income Taxes (Significant Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Stock-based compensation expense	$ 421	$ 291
Accrued employee benefits	463	387
Accruals and reserves not currently deductible	1,047	902
Tax credits	3,264	1,979
Basis difference in investment in Arris	0	657
Prepaid cost sharing	0	597
Net operating losses	771	557
Operating leases	1,876	160
Other	390	21
Total deferred tax assets	8,232	5,551
Valuation allowance	(3,502)	(2,817)
Total deferred tax assets net of valuation allowance	4,730	2,734
Deferred tax liabilities:
Property and equipment, net	(1,798)	(1,382)
Renewable energy investments	(466)	(500)
Foreign Earnings	(373)	(111)
Net investment gains	(1,074)	(1,143)
Operating leases	(1,619)
Other	(380)	(125)
Total deferred tax liabilities	(5,710)	(3,261)
Deferred tax liabilities, net	$ (980)	$ (527)