In WWE/TNA, How Pre-Planned Are Matches?

It is no secret that pro wrestling matches are planned out in advance with a winner being chosen before the match takes place. 

But how much involvement does the creative/writers team have in what happens in matches?

TNA and WWE have two different styles of wrestling, and it shows pretty heavily in their matches.  TNA seems to have a more fast-paced style while WWE focuses more on the story telling aspect of their matches.

Writers and creative team members book the matches, and even plan some of the moves ahead of time.  This is especially true in gimmick matches, like ladder and cage matches.

So how much input or freedom does a wrestler really have?

It is obvious to most people when something happens that wasn't supposed to happen. 

For example, Kurt Angle recently took a nasty spill outside the ring during a ladder match.  He was supposed to grab the ropes and land on the apron, but instead he fell over ten feet to the thinly padded matc below.

This bump forced him to take some time off, but not after having a cage match with Mr. Anderson where he moon-saulted off the top of the cage. 

Other people who seem to have planned matches are the motor city machine guns.  So many of their moves are double team moves that would be hard to pull off without the opponent knowing they are coming.

Booker-T once said in an interview that during a match Brock Lesnar gave him a belly to belly suplex instead of the planned back body drop, and the move worked out perfectly.

Another instance where an unplanned move did not work so well was when Mick Foley was choke-slammed onto the top of the hell in the cell structure, and crashing through to the mat.

This was not planned in advance, the WWE has admitted that the cage broke by accident and Foley was not supposed to take two 20 foot falls in the same match. 

While the incident cemented Foley's hardcore legacy, it cut his career short as well.  Taking bumps like that always do.

So while it seems that some moves are planned, some aren't.

So my question is, how much control do the wrestlers have over what happens in a match and how much involvement does the writing team have in moves that take place in matches?