SoftBank is not a telecom, it's a holding company like Berkshire.
http://www.berkshirehathawayhs.com/
They also own 100% of a heck of a lot of subsidiaries. They're not just minority owners in a bunch of companies like Coca-Cola.
https://en.wikipedia.org/wiki/List_of_assets_owned_by_Berksh...
If you're good at writing insurance it's essentially a great way of getting interest-free loans which they then spin into a huge pile of low-risk, cash-generating businesses (e.g. Duracell, Fruit of the Loom, See's Candies, to pick three Berkshire brands...).
They're an insurance company which monetizes through operating businesses rather than the traditional model of bancassurance.