Stock-based Compensation - Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 286	$ 277	$ 287
COR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	47	48	49
R&D
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	60	62	67
SG&A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	169	156	160
Acquisition charges
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 10	$ 11	$ 11