I am replacing the feed from my main panel to the sub panel with
number 3 wire in 1 1/4 inch conduit. I have the wire disconnected from
my sub panel.

I have the feeder breaker off feeding the sub panel. (The 100 amp
feeder breaker at the main panel).

I know I have to turn off the main 200 amp breaker at the main panel,
but is there any voltage at the neutral wire? I know the main breaker
has no connection to the neutral coming in from the power company. (I
dont think). Will I be safe to just turn off the main breaker,
disconnect my wire feeding the sub panel includign the neutral to the
neutral bus?