Stephen Schwartzman, CEO Blackstone Group

America's long-term deficit problems can be solved by going back to a ratio of government spending to tax revenue that had worked for decades, Blackstone Group CEO Steve Schwarzman told CNBC.

The easiest way for President Barack Obama and Republicans to reach a "fiscal cliff" deal would be for spending to revert to 20 percent of the nation's gross domestic product, with taxes at 18 percent, he said on CNBC's "Squawk Box" Wednesday.