Thanks for the link Four Reds. In that document, there is a nice picture of the widening at section 4-5-5, page 2. That level of detail is beyond the usual operational interest, and most airline airport compatibility studies simply look at the width of the straight sections of taxiway.
The planes which require special attention to widening at corners (i.e. the provision of generous fillets) are the very long wheelbase ones, such as the A340-5/600, 777-300/ER, 747-800, AN225 and A380.