Our product teams and Comcast Interactive Media are focused on developing integrated services that offer entertainment and communications to consumers across multiple platforms. Our programming networks are also working on that strategy. PBS KIDS Sprout is available on a linear channel, on demand and online. In October 2006, we launched FEARnet, a new advertising-supported, multiplatform network delivering the best of modern horror films, streaming video and original content — on demand, online and to mobile devices.
With our cable partners and Sprint Nextel, we are testing consumer demand and applications to integrate and extend the Comcast experience outside the home, bringing mobility to our products. We also invested in wireless spectrum with a nationwide reach as part of the SpectrumCo consortium. This spectrum gives us strategic flexibility and many options to capitalize on new wireless functionalities as they evolve.
Our strong balance sheet and free cash flow(d) give us significant financial flexibility to innovate, invest and grow. In 2006, we focused our investments in cable and programming to drive new product RGUs, to enhance our services and to launch new businesses. We generated over $2.6 billion in free cash flow and used $2.3 billion to repurchase our stock. In fact, over the past three years, we have invested virtually all of our free cash flow in our stock and securities exchangeable into our stock, reducing our shares outstanding by more than 10%.
On a Mission to Grow
In 2007, we will focus even more intently on growing RGUs to capture market share and extend our leadership in the market. In the last five years, we have transformed Comcast into a company that develops and delivers multiple services with diverse revenue streams. Over the next few years, it is easy to imagine that our company could be serving as many high-speed Internet and digital voice customers as we have video customers today.
The first quarter of 2007 marks a bittersweet milestone with the retirement of Larry Smith, our Co-Chief Financial Officer. Over the years, I have called Larry the company's "chief money-making officer." He has made phenomenal contributions to Comcast's growth and success — his deal-making prowess, wise counsel and steady leadership are a huge part of Comcast's culture. His friendship and guidance will continue as he remains a part-time advisor in the future. We are thrilled to have recruited Michael Angelakis, a managing director in the extremely successful Providence Equity Partners, to succeed Larry. Michael will partner with John Alchin in 2007 as Co-CFO and will succeed John when he retires at the end of 2007.