Goodwill and Other Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	May 28, 2016	May 30, 2015	Feb. 27, 2016
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	$ 2,833,297		$ 2,819,815
Accumulated Amortization	(1,902,088)		(1,848,936)
Net	931,209		970,879
Gross Carrying Amount of Indefinite Lived	33,500
Gross Carrying Amount, Total	2,866,797		2,853,315
Net, Total	964,709		1,004,379
Unfavorable lease intangibles	45,525		46,947
Amortization expense for intangible assets and liabilities	55,503	$ 31,941
Anticipated annual amortization expense for intangible assets and liabilities
2017	214,640
2018	172,135
2019	134,730
2020	105,199
2021	72,517
Trademarks
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Indefinite Lived	33,500		33,500
Favorable leases and other
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	665,143		665,197
Accumulated Amortization	(514,173)		(507,776)
Net	$ 150,970		$ 157,421
Remaining Weighted Average Amortization Period	8 years		8 years
Prescription files
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	$ 1,555,054		$ 1,541,518
Accumulated Amortization	(1,312,073)		(1,285,633)
Net	$ 242,981		$ 255,885
Remaining Weighted Average Amortization Period	3 years		3 years
Customer relationships
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	$ 465,000		$ 465,000
Accumulated Amortization	(60,374)		(44,203)
Net	$ 404,626		$ 420,797
Remaining Weighted Average Amortization Period	16 years		17 years
CMS license
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	$ 57,500		$ 57,500
Accumulated Amortization	(2,147)		(1,572)
Net	$ 55,353		$ 55,928
Remaining Weighted Average Amortization Period	24 years		25 years
Claims adjudication and other developed software
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	$ 59,000		$ 59,000
Accumulated Amortization	(7,867)		(5,760)
Net	$ 51,133		$ 53,240
Remaining Weighted Average Amortization Period	6 years		7 years
Trademarks
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	$ 20,100		$ 20,100
Accumulated Amortization	(1,876)		(1,373)
Net	$ 18,224		$ 18,727
Remaining Weighted Average Amortization Period	9 years		10 years
Backlog
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	$ 11,500		$ 11,500
Accumulated Amortization	(3,578)		(2,619)
Net	$ 7,922		$ 8,881
Remaining Weighted Average Amortization Period	2 years		3 years