The media conglomerate reported a $44.9bn net loss for the quarter, compared with a loss of only $1.8bn for the same period a year ago.
The non-cash goodwill charge was taken to reflect the decline in value of America Online and other intangible assets that the company is carrying.
For the full year the company reported a net loss of $98.7bn, compared with a net loss of $4.93bn for the previous year.
Although the charge had been expected given the continued weakness of AOL, Turner's resignation came as a surprise. Chief executive officer Dick Parsons said Turner would leave in May to "pursue philanthropic interests".
Earlier this month that AOL Time Warner reported that chairman and AOL founder Steve Case would be stepping down in May.
With AOL in trouble, the company has been searching high and low for a way to cut costs and boost revenue.
On Tuesday the company sold its 8.4% stake in satellite-based networks and Internet service Hughes Electronics for roughly $800m in an effort to lighten its debt load and is rumoured to be shopping around its book publishing division in hopes of further filling its coffers.