Recent Accounting Pronouncements (Details) - USD ($)	3 Months Ended			9 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Apr. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Goodwill impairment losses	$ 53,000,000		$ 0	$ 2,940,000,000	$ 0
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets						$ 1,700,000,000
Lease liabilities						$ 1,800,000,000
Accounting Standards Update 2017-04
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Goodwill impairment losses		$ 2,940,000,000
GBS
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Goodwill impairment losses				2,675,000,000
GBS | Accounting Standards Update 2017-04
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Goodwill impairment losses		2,675,000,000
GIS
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Goodwill impairment losses				$ 265,000,000
GIS | Accounting Standards Update 2017-04
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Goodwill impairment losses		$ 265,000,000