My father died last year, and had previously left all his children a copy of what he called his 'laundry list'. It covered pretty much everything you can imagine, in great detail. From memory:
Utilities - gas / electric / water / council tax: all account numbers, contact phone numbers, DD amount and correspondence address.
Bank accounts - account numbers, sort codes, regular incomings / outgoings, phone numbers / correspondence addresses.
Investments - where to find relevant paperwork, investment account numbers, phone numbers, correspondence addresses
Credit cards - account numbers, where to find all receipt slips for the last 2 months (used to keep them unti lthe bill came in, check them off and then shred), correspondence addresses.
Pension (occupational) - contact details for pension provider, pension reference number, NI number, pension amount, where to find payslips so i could calculate if an income tax rebate was due.
Pension (state) - NI number, relevant contact details, pension amount
House - where deeds held (no mortgage), where to find warranties etc
TV license - where to find, renewal date
Insurance - where to find policies, policy numbers, renewal dates
Car - where to find ownership documents
Where to find important documents eg marriage license, birth certificate, original will.
List of all direct debits and standing orders, including charitable donations made with gift aid.
List of all gifts made in the last 7 years (relevant for inheritance tax).
His wishes regarding funeral / burial, including contact details for various friends who he specifically wanted to invite.
Also in the letter was his views on what order we should inform companies etc in (eg, informing the credit card company before informing the bank to ensure that a DD wasn't refused because the account was frozen), how to register the death, and a sort of 'first steps to take' (eg, if he died at home, contact his doctor, contact funeral company etc).
I was one of the executors of his estate (my mother being the other). My mum had had absolutely no input into the finances really and having all the information we needed spelled out clearly made what was a hard task at a difficult time so much easier, especially as my mum really wasn't up to much right after my dad died (they'd been married since she was 16 - 47 years). Me and DH have now written our own, and have also included things like email passwords, facebook passwords etc.
Does that help at all?