Income Taxes (Income Tax Payables and Income Tax Receivables) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Income taxes receivable—current	$ 206	$ 294
Income taxes receivable—noncurrent	0	15
Total income taxes receivable	206	309
Income taxes payable—current	322	393
Income taxes payable—noncurrent	2	2
Total income taxes payable	$ 324	$ 395