Social Security faces a $5.3 trillion shortfall over the next 75 years, but a new congressional report says the massive gap could be erased with only modest changes to payroll taxes and benefits.

Some of the options are politically dangerous, such as increasing payroll taxes or reducing annual cost-of-living increases for Social Security recipients. Others, such as gradually raising the age when retirees qualify for full benefits, wouldn't be felt for years but would affect millions.