Basis of Presentation - Reclassification (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended			12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019		Jun. 30, 2020	Jun. 30, 2019		Dec. 31, 2019
Revenues	$ 18,123	$ 19,161		$ 35,694	$ 37,342		$ 77,000
Cost of Revenue	9,423	10,151		19,071	20,290
Services
Revenues	10,937	11,836	[1]	22,311	23,751	[1]
Cost of Revenue	7,520	8,181	[1]	15,363	16,453	[1]
Sales
Revenues	6,918	6,974	[1]	12,813	12,836	[1]
Cost of Revenue	$ 1,739	1,741	[1]	$ 3,363	3,344	[1]
Adjustment
Revenues							$ 300
Adjustment | Services
Revenues		(500)			(1,000)
Cost of Revenue		(100)			(200)
Adjustment | Sales
Revenues		500			1,000
Cost of Revenue		$ 100			$ 200

[1] Reclassified to conform to current period presentation. Refer to note 1, “Basis of Presentation,” for additional information.