Subsequent Events (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) position	Feb. 27, 2015 USD ($)
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 2,500
line of credit available increase to credit facility		$ 1,000
Subsequent Event | Minimum
Subsequent Event [Line Items]
Expected cost of restructuring	$ 250
Subsequent Event | Maximum
Subsequent Event [Line Items]
Restructuring and Related Cost, Expected Cost, to be Settled with Cash	$ 220
Subsequent Event | VMware
Subsequent Event [Line Items]
Restructuring and Related Cost, Expected Number of Positions Eliminated | position	800
Subsequent Event | VMware | Minimum
Subsequent Event [Line Items]
Expected cost of restructuring	$ 55
Subsequent Event | VMware | Maximum
Subsequent Event [Line Items]
Expected cost of restructuring	$ 65