Subsequent Events (Details) - Subsequent Event - Senior Notes - USD ($)	Apr. 01, 2016	Apr. 30, 2016
Subsequent Event [Line Items]
Debt instrument face amount		$ 2,500,000,000.0
Redemption price of debt instrument (as a percent)	100.00%
July 15, 2021
Subsequent Event [Line Items]
Debt instrument face amount	$ 500
Months to maturity date	1 month
July 15, 2021 | Senior notes maturing in 2021 before the date that is one month prior to the maturity date
Subsequent Event [Line Items]
Redemption price of debt instrument (as a percent)	100.00%
July 15, 2026
Subsequent Event [Line Items]
Debt instrument face amount	$ 1,000
Months to maturity date	3 months
July 15, 2026 | Senior notes maturing in 2026 before the date that is three months prior to the maturity date
Subsequent Event [Line Items]
Redemption price of debt instrument (as a percent)	100.00%
April 1, 2046
Subsequent Event [Line Items]
Debt instrument face amount	$ 500
Months to maturity date	6 months
April 1, 2046 | Senior notes maturing in 2045 before the date that is six months prior to the maturity date
Subsequent Event [Line Items]
Redemption price of debt instrument (as a percent)	100.00%
April 2019 and July 2021
Subsequent Event [Line Items]
Debt instrument face amount	$ 1,000,000,000.0
Redemption price of debt instrument (as a percent)	101.00%