Proposed Healthcare Technology Net Asset Exchange (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Jun. 30, 2017	Mar. 31, 2016
Schedule of Equity Method Investments [Line Items]
Current assets held for sale	$ 1,767	$ 1,767		$ 635
Current liabilities held for sale	604	604		$ 660
Core MTS Businesses | Held-for-sale, Not Discontinued Operations
Schedule of Equity Method Investments [Line Items]
Current assets held for sale	1,767	1,767
Current liabilities held for sale	604	604
Joint Venture | Expected
Schedule of Equity Method Investments [Line Items]
Expected ownership interest in the joint venture (percent)			70.00%
Joint Venture
Schedule of Equity Method Investments [Line Items]
Debt financing commitments received	6,100	6,100
Change Healthcare | Joint Venture | Expected
Schedule of Equity Method Investments [Line Items]
Expected ownership interest in the joint venture (percent)			30.00%
Operating Expenses | Technology Solutions | Joint Venture
Schedule of Equity Method Investments [Line Items]
Expenses associated with the formation of the joint venture	$ 21	$ 25