Income Taxes (Details) € in Millions, $ in Millions		1 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	Oct. 04, 2017 EUR (€)	Jun. 30, 2015 EUR (€)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Income Tax Disclosure [Abstract]
Provision for income taxes			$ 58		$ 229	$ 755	$ 1,012
Discrete tax benefits						422	50
Valuation allowance against the net deferred tax assets				$ 600
Cash taxes paid, net of refunds			172		$ 91	865	$ 317	$ 960	$ 390
Tax contingencies			$ 2,100			2,100		$ 2,100		$ 1,700
Internal Revenue Service (IRS) | Domestic Tax Authority [Member]
Income Tax Examination [Line Items]
Tax examination, estimate of additional tax expense						$ 1,500
French Tax Administration | Foreign Tax Authority [Member]
Income Tax Examination [Line Items]
Tax examination, estimate of additional tax expense | €		€ 196
Subsequent Event [Member] | European Commission | Foreign Tax Authority [Member]
Income Tax Examination [Line Items]
Tax examination, estimate of additional tax expense | €	€ 250