Income Taxes Income Taxes (Schedule of Effective Tax Rate Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes [Line Items]
Income tax provision computed at US federal statutory tax rate	$ 171	$ 329	$ 563
Change in valuation allowance	124	49	89
Equity income and dividends	(33)	(50)	(44)
(Income) expense not resulting in tax impact, net	(32)	(34)	(33)
US tax effect of foreign earnings and dividends	15	49	35
Foreign tax credits	(4)	(34)	(38)
Other foreign tax rate differentials	(41)	(33)	(55)
Legislative changes	0	0	(19)
Tax-deductible interest on foreign equity investments and other related items	0	12	11
State income taxes, net of federal benefit	6	9	11
Other, net	(5)	17	(12)
Income tax provision (benefit)	$ 201	$ 314	$ 508
Effective income tax rate	41.00%	33.00%	32.00%
UNITED STATES
Income Taxes [Line Items]
US federal statutory tax rate	35.00%