Income Taxes (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 15, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Unrecognized Tax Benefits		$ 506		$ 506				$ 1,238
Unrecognized Tax Benefits that Would Impact Effective Tax Rate		$ 432		432				1,150
Payments for Legal Settlements	$ 303
Litigation Settlement Interest	$ 307
Tax Adjustments, Settlements, and Unusual Provisions				$ 250
Reported tax rate		(60.30%)	(60.30%)	(27.30%)	(10.10%)
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total		$ 78		$ 78				$ 655
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense		2	$ 13	19	$ 26
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent								35.00%
Tax Cuts and Jobs Act, Measurement Period Adjustment, Income Tax Expense (Benefit)		$ 28		37
Tax Cuts and Jobs Act, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Expense (Benefit)								$ 99
Tax Cuts and Jobs Act, Incomplete Accounting, Provisional Income Tax Expense (Benefit)				824
Tax Cuts and Jobs Act, Incomplete Accounting, Transition Tax for Accumulated Foreign Earnings, Provisional Liability				866
Tax Cuts and Jobs Act, Incomplete Accounting, Transition Tax for Accumulated Foreign Earnings, Provisional Liability Net Existing				$ 506
Subsequent Event [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent							21.00%
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities						$ 221