Is There a Benchmark for Repurchases?

Berkshire's insurance operations currently allowed to declare up to 16 billion as ordinary dividends during 2018. If Berkshire wanted to buy back more stock than that or pay out even more as dividends would there be an issue with you using capital from operations that aren't held by the insurance operations to return additional capital? Warren Buffett: "If repurchases were really attractive, we would do it in a very big way"