But it may not be so simple, some EV segment observers believe.
Owners of the Nissan Leaf, Chevrolet Bolt, Porsche Taycan, Jaguar I-Pace and Mustang Mach-E, for example, could find using the Superchargers to be a challenge.
Tesla vehicles sold in North America are built with a proprietary plug that is not compatible with other brands' EVs. In Europe, Tesla uses a standard plug. There is an adapter available for Tesla's Level 2 or Destination Chargers, but not for the Superchargers Musk wants to open up.
"Some sort of adapter will be needed," says Sam Abuelsamid, principal analyst for E-Mobility Research at Guidehouse Insights. "Tesla could add some chargers with [combined charging system] connectors or offer some kind of adapter that allows CCS vehicles to be plugged into Superchargers."
Another issue is that, unlike the chargers from Electrify America, EVgo and other networks, Tesla Superchargers don't have a screen or a way to swipe a credit card or enter payment details.
Musk's proposal could also require more cooperation with outside companies. EVs and chargers have to communicate with each other to ensure compatibility. That means that apps will need to be developed, possibly by both Tesla and other automakers, to allow the charging "handshake" to take place between the Tesla charger and the non-Tesla vehicle.
The next challenge would be whether Tesla could even create an adapter and an app on Musk's end-of-year timeline. The automaker has more pressing issues right now, including the construction of two assembly plants and the development of new vehicles, such as the Cybertruck and its electric semitruck.
But Abuelsamid thinks at least some of the software and payment issues could be solved if Tesla enabled owners of other brand vehicles to sign up for a Tesla charging account.
"Plug and charge" software could be one way a non-Tesla vehicle could work with a Supercharger. It enables a customer to simply plug in an EV, then the vehicle and the charger connect, and billing is handled automatically through the app.
"It certainly has not been a smooth launch for Electrify America, the first network to use plug and charge," he said.
"There will probably be some challenges for the first cars to use Superchargers."
Opening Superchargers to other brands could help Tesla offset some of the capital expenditures related to its new plants and vehicles, the automaker acknowledged.
"Increasing the utilization of the network actually reduces our costs, which allows us to lower charging prices for our customers and make the network more profitable," Andrew Baglino, Tesla's, senior vice president, powertrain and energy engineering, said during the conference call.
But Tesla customers have already grumbled online about the idea of sharing their Superchargers.
A Twitter user going by the name of Ehud Karassik replied to Musk's Supercharger tweet with: "That's a shame! That is the thanks you give all Tesla owners who believed in you and bought your product? The joy of seeing Tesla superchargers jammed with old Nissan Leafs and Chevy Bolts?"