Segment Information (Narrative) (Details) (USD $)	3 Months Ended						9 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Litigation charges	$ 18,000,000			$ 0			$ 68,000,000	$ 60,000,000
Charges associated with last-in-first-out inventory method							186,000,000	5,000,000
Gain on business combination	0			0			0	81,000,000
Average Wholesale Price Litigation [Member]
Segment Reporting Information [Line Items]
Litigation charges	18,000,000	35,000,000	15,000,000	0	44,000,000	16,000,000	68,000,000	60,000,000
Distribution Solutions [Member]
Segment Reporting Information [Line Items]
Percentage of Revenue Derived From Services	less than 2%			less than 2%			less than 2%	less than 2%
Distribution Solutions [Member] | Operating expense [Member] | RAMQ [Member]
Segment Reporting Information [Line Items]
Litigation charges				40,000,000				40,000,000
Distribution Solutions [Member] | Operating expense [Member] | Average Wholesale Price Litigation [Member]
Segment Reporting Information [Line Items]
Litigation charges	18,000,000						68,000,000	60,000,000
Distribution Solutions [Member] | Cost of sales [Member]
Segment Reporting Information [Line Items]
Charges associated with last-in-first-out inventory method	142,000,000			2,000,000			186,000,000	5,000,000
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Gain on business combination								81,000,000
Antitrust Class Action Lawsuit [Member] | Distribution Solutions [Member] | Cost of sales [Member]
Segment Reporting Information [Line Items]
Litigation Settlement, Amount	$ 27,000,000			$ 8,000,000			$ 34,000,000	$ 27,000,000