Stock-Based Compensation (Narrative) (Details) - Blue Coat, Inc. shares in Millions, $ in Millions	Aug. 01, 2016 USD ($) plan shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity incentive plans assumed | plan	2
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Assumed awards, fair value | $	$ 265
Stock Options, Vested
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Assumed awards (in shares)	7.5
Stock Options, Unvested
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Assumed awards (in shares)	12.5
Performance Shares and Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Assumed awards, fair value | $	$ 162
Restricted stock units:
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Assumed awards (in shares)	4.8
Performance-based restricted stock units:
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Assumed awards (in shares)	3.0