Short-term Financing (Details) - USD ($)	3 Months Ended			6 Months Ended
	Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2018		Dec. 31, 2017	Jun. 30, 2018
Short-term Debt [Line Items]
Short-term debt	$ 0			$ 0
Commercial paper	1,206,000,000	[1]		1,206,000,000	[1]		$ 0
Obligations under reverse repurchase agreements	0			$ 0			$ 0
Maturities of short-term funding agreements				overnight to up to five business days
364-day credit agreement
Short-term Debt [Line Items]
Maximum borrowing capacity under credit facilities	3,800,000,000			$ 3,800,000,000
Term of credit agreement				364 days
Expiration date of credit facilities				Jun. 16, 2019
Extension option term				1 year
Credit Facility Expiring In June 2022
Short-term Debt [Line Items]
Maximum borrowing capacity under credit facilities	2,250,000,000			$ 2,250,000,000
Term of credit agreement				5 years
Expiration date of credit facilities				Jun. 17, 2022
Line of credit facility potentially available increase in maximum borrowing capacity				$ 500,000,000
Credit Facility Expiring In June Two Thousand Twenty Three [Member]
Short-term Debt [Line Items]
Maximum borrowing capacity under credit facilities	3,750,000,000			$ 3,750,000,000
Term of credit agreement				5 years
Expiration date of credit facilities				Jun. 13, 2023
Line of credit facility potentially available increase in maximum borrowing capacity				$ 500,000,000
Commercial paper program
Short-term Debt [Line Items]
Short-term Debt, Maximum Borrowing Capacity				$ 9,800,000,000
Maturities of commercial paper range				overnight to up to 364 days
Short-term debt, average outstanding amount	$ 3,800,000,000		$ 3,500,000,000	$ 3,800,000,000		$ 3,700,000,000
Debt instrument, interest rate during period	2.30%		1.20%	2.10%		1.20%
Short Term Commercial Paper Program
Short-term Debt [Line Items]
Commercial paper weighted average maturity				2 days		2 days
Reverse repurchase agreements
Short-term Debt [Line Items]
Short-term debt, average outstanding amount	$ 325,400,000		$ 537,000,000	$ 410,200,000		$ 531,600,000
Debt instrument, interest rate during period	1.90%		1.20%	1.80%		1.10%

[1] As of December 31, 2018, $1,206.0 million of cash and cash equivalents are related to the Company's outstanding commercial paper borrowings (see Note 10).