CALGARY -- TransCanada Corp. is filing its regulatory application for the proposed Energy East pipeline today.

TransCanada says the document being submitted to the National Energy Board will be one of the most comprehensive in the company's history.

The $12-billion project would be one of the biggest infrastructure projects ever built in Canada, spanning six provinces and 4,600 kilometres.

It would ship Alberta crude through pipe that's already in the ground for two thirds of the way, with new pipeline being built through Quebec and New Brunswick.

Energy East would deliver crude to export terminals planned for Quebec and New Brunswick, enabling shipments to Europe, India and other destinations.

It's also meant to feed lower-cost domestic crude to eastern refineries, which TransCanada says depend on more expensive foreign crude.