Income Taxes (Unaudited) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jun. 30, 2016
Income Tax Contingency [Line Items]
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Amount	$ 21		$ 59
Income Tax Expense (Benefit)	$ 213	$ 221	$ 638	$ 673
Effective income tax rate	29.20%	31.80%	29.40%	30.10%
Tax Adjustments, Settlements, and Unusual Provisions			$ 51
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ (75)		$ (75)
Maximum | Scenario, Forecast [Member]
Income Tax Contingency [Line Items]
Tax Adjustments, Settlements, and Unusual Provisions					$ (40)