Akamai recently deflected an attack on the scale of 1 TBit/s and is present in pretty much every DC (~1000 POPs). CloudFlare has 23 POPs and brags about handling 65 GBit/s...
Akamai got into that many POPs by "giving away free bandwidth saving appliances" to the ISPs rather than paying to host their commercial edge CDN in a their DCs. Full marks to whoever came up with that spin! (This was circa 1999/2000).
there are some public studies on DDOS size over the years. IIRC Arbor networks published some numbers earlier this year. IME tens of Gb/s is a mid size attack these days. Large is a hundred plus Gb/s.
I can't find any public reports topping ~100 Gbps. For example, here's a recent article that interviewed an Arbor employee and mentions a ~100 Gbps plateau:
Hrm, maybe Im misrembering. Found akamai claiming 125Gb/s in '09, and some more arbor quotes of ~110Gb/s. I'll see if I still have the report Im thinking of tomorrow.