Does Verizon use encryption for its fiber telephone service ?

Many Voip services like Google Voice do not encrypt its data packages yet some do like skype, . So my question is, does Verizon VOIP telephone us any encryption in its proprietary comm protocol. If so, to what degree of encryption do they use?

This is not related to the current news of government eavesdropping.

Can I set my Verizon router model Actiontec MI424... to encrypt VOIPs like google voice without the need to use a VPN ?