Aviva said it will sell or close 16 underperforming businesses as part of a shake-up aimed at re-inforcing its finances and reinvigorating its flagging share price.
The move comes only weeks after the departure of chief executive Andrew Moss following a shareholder rebellion over his pay package and the company's stock market performance.
The businesses earmarked for disposal include its South Korean arm and its British large-scale bulk purchase annuity unit. Between them they contribute £300 million after-tax profit, Aviva said.
It also revealed plans to sell a 15% stake in its Dutch and Belgium subsidiary, Delta Lloyd.
Aviva has identified a further 27 businesses which "require significant improvement", including its Irish general insurance arm, which between them produce £750m of operating profit after tax.
The company said that 15 businesses, including its UK Personal Property and UK Life Protection arms which produce £650m operating profit after tax, are producing unusually high returns or levels of growth.
The disposal plan is the culmination of a two-month scrutiny of Aviva's 58 businesses launched by executive chairman John McFarlane, another Scot who took day-to-day control of the group after Moss quit on May 8.
The company also plans to scrap four of its nine levels of management.
Mr McFarlane said: "I realise I am asking for a great deal of faith and trust from shareholders, particularly given our recent history. I also realise the current economic climate makes our task more arduous."
But he added: "I am confident we will be successful."
In comments that implicitly criticise the way the company was run by Mr Moss, Mr McFarlane said that investors viewed Aviva as too complex, are nervous about its financial strength, think it is too exposed to the eurozone and has few high-growth businesses.
Mr McMillan, who previously ran Aviva's general insurance business in the UK & Ireland, has been appointed director of group transformation to manage the new strategic plan.
Robin Spencer will replace Mr McMillan as chief executive, UK & Ireland General Insurance.
Aviva said its human resources director John Ainley has decided to leave the business.
Mr McMillan is part of a five-strong Office of the Chairman that will oversee the running of Aviva. Its members includes Trevor Matthews, the former Standard Life executive who is Aviva's executive director for developed markets. A new chief executive is due to be appointed by the New Year.
It is understood that the proposed changes are unlikely to have much impact on its operations in Scotland because they tend to have front-line roles.
Aviva employs 1500 people in Perth to handle all the group's household claims, and housing its top-end underwriting expertise on commercial insurance.
Another 900 at Bishopbriggs near Glasgow run call centre-based sales and service for various brands and manage bodily injury claims.
Mr McFarlane, who previously served on the board of Royal Bank of Scotland, said: "I am aware of past concerns regarding the frequency of management changes at Aviva; nevertheless I judge these new appointments to be essential."
Barrie Cornes, analyst at Panmure Gordon, said: "The announcements appears logical and sensible given where Aviva is today, and in our view the new strategy could well prove to be the turning point for long-suffering shareholders."
Aviva's investors appeared to react positively to the update, sending its shares up 6.6p or 2.4% to 288p.