The budget-busting measure includes trillions in tax cuts for the wealthy and corporations along with harsh cuts to Medicaid and food stamps.

A new analysis showing the legislation would be far more expensive than the House version could complicate its chances of final passage in that chamber, where fiscal hawks have said the cost must not grow.

The Senate has started formal debate on the Trump administration's budget reconciliation bill after lawmakers spent 16 hours reading the entire measure aloud on the Senate floor.