Medicare

Medicare has four parts:

1. Medicare Part A, instituted in 1965, which contributes to nursing care, inpatient hospital care, home and hospice care.  
2. Medicare Part B, instituted in 1965, which contributes to physician services, outpatient hospital care, and other medical services.
3. Medicare Part C, or "Medicare Advantage" instituted in 1997/2003, substitutes the services of Part A and Part B, but are offered through a private entity (with a part of payments made by the government).
4. Medicare Part D, or "Medicare Prescription Drug Benefit" instituted in 2003/2006 subsidizes prescription drugs supplied through a private entity.

In 2012, the U.S. spent $536 billion on Medicare expenditures, and Corrections breaks down that spending by type (click to enlarge).