Pension Benefits - Narrative (Details)	1 Months Ended	3 Months Ended			12 Months Ended
	Jun. 30, 2019 USD ($) participant	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2020 USD ($) $ / shares	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Actuarial losses from pension plans					$ 127,000,000	$ 0	$ 0
Percentage of eligible compensation (up to)					75.00%
Contribution expenses					$ 102,000,000	92,000,000	82,000,000
First Part Of Pay Contribution
Defined Benefit Plan Disclosure [Line Items]
Company match employee contributions (as a percent)					100.00%
Employee contributions (as a percent)					3.00%
Second Part Of Pay Contribution
Defined Benefit Plan Disclosure [Line Items]
Company match employee contributions (as a percent)					50.00%
Employee contributions (as a percent)					2.00%
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Highest average pay period					60 months
Plan years prior to freeze date					15 years
Unexpected actuarial losses (as a percent) (exceeding)					10.00%
Expected amortization of actuarial loss					$ 5,000,000	8,000,000
Expected benefit payments in 2021					36,000,000
Expected benefit payments in 2022					35,000,000
Expected benefit payments in 2023					36,000,000
Expected benefit payments in 2024					36,000,000
Expected benefit payments in 2025					38,000,000
Expected benefit payments in 2026 through 2030					208,000,000
Expected contributions in next fiscal year					$ 33,000,000
Unit value of cash and cash equivalents (in dollars per share) | $ / shares					$ 1.00
United States | Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Number of plan participants elected to receive settlement payments | participant	1,300
Settlement payments made	$ 49,000,000
Pre-tax pension settlement charges			$ 105,000,000	$ 17,000,000	$ 122,000,000
After-tax pension settlement charges			78,000,000	$ 12,000,000	90,000,000
Annuity contracts purchased			$ 280,000,000
Accumulated pension obligation					0	121,000,000
Current liabilities					1,000,000	115,000,000
Actuarial loss					129,000,000	9,000,000	8,000,000
Projected benefit obligation					$ 10,000,000	$ 439,000,000	485,000,000
Discount rates					3.08%	3.65%
Increase (decrease) in basis points					(0.0057)
United States | Pension Plans, Defined Benefit | Fixed Income Investments
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)					100.00%
United States | Pension Plans, Defined Benefit | Unfunded plan
Defined Benefit Plan Disclosure [Line Items]
Pre-tax pension settlement charges		$ 11,000,000
After-tax pension settlement charges		8,000,000
Accumulated pension obligation					$ 1,000,000	$ 12,000,000
Amounts of plan exceeding total plan contribution		$ 114,000,000
Projected benefit obligation					10,000,000	124,000,000
Non-U.S. Plans | Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Amounts of plan exceeding total plan contribution					17,000,000	27,000,000	16,000,000
Current liabilities					162,000,000	13,000,000
Actuarial loss					6,000,000	5,000,000	6,000,000
Projected benefit obligation					$ 896,000,000	$ 990,000,000	$ 1,035,000,000
Discount rates					2.03%	2.13%
Increase (decrease) in basis points					(0.0010)
Percentage of total plan contribution - exceeding					5.00%
Funded status (as a percent)					76.00%
Amounts accrued for liability					$ 0
Non-U.S. Plans | Pension Plans, Defined Benefit | Norwegian Public Service Pension Fund (SPK)
Defined Benefit Plan Disclosure [Line Items]
Amount of plan asset value					29,000,000	$ 35,000,000
Non-U.S. Plans | Pension Plans, Defined Benefit | Held-for-sale
Defined Benefit Plan Disclosure [Line Items]
Current liabilities					151,000,000
Non-U.S. Plans | Pension Plans, Defined Benefit | Unfunded plan
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation					298,000,000	$ 293,000,000
Termination of U.S Defined Benefit Pension Plan and Settlement of Retirement Benefits | United States | Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss					127,000,000
Termination of U.S Defined Benefit Pension Plan | United States | Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Actuarial losses from pension plans					116,000,000
Settlement of Executive Retirement Benefits | Retired executive | United States | Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Actuarial losses from pension plans					$ 11,000,000