Income Taxes (Summary of Operating Loss And Tax Credit Carryforwards) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Operating loss and tax credit carryforwards	$ 1,211
Two Thousand Fifteen Through Two Thousand Twenty Four [Member]
Operating Loss Carryforwards [Line Items]
Operating loss and tax credit carryforwards	372
Two Thousand Twenty Five Through Two Thousand Thirty Four [Member]
Operating Loss Carryforwards [Line Items]
Operating loss and tax credit carryforwards	102
Indefinite Life [Member]
Operating Loss Carryforwards [Line Items]
Operating loss and tax credit carryforwards	737
U.S. Federal, Non-U.S. and State and Local Jurisdiction [Member] | General Business Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	444
U.S. Federal, Non-U.S. and State and Local Jurisdiction [Member] | Two Thousand Fifteen Through Two Thousand Twenty Four [Member] | General Business Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	146
U.S. Federal, Non-U.S. and State and Local Jurisdiction [Member] | Two Thousand Twenty Five Through Two Thousand Thirty Four [Member] | General Business Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	23
U.S. Federal, Non-U.S. and State and Local Jurisdiction [Member] | Indefinite Life [Member] | General Business Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	275
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	216
State and Local Jurisdiction [Member] | Capital Loss Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	58
State and Local Jurisdiction [Member] | Two Thousand Fifteen Through Two Thousand Twenty Four [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	140
State and Local Jurisdiction [Member] | Two Thousand Fifteen Through Two Thousand Twenty Four [Member] | Capital Loss Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	58
State and Local Jurisdiction [Member] | Two Thousand Twenty Five Through Two Thousand Thirty Four [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	76
State and Local Jurisdiction [Member] | Two Thousand Twenty Five Through Two Thousand Thirty Four [Member] | Capital Loss Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	0
State and Local Jurisdiction [Member] | Indefinite Life [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	0
State and Local Jurisdiction [Member] | Indefinite Life [Member] | Capital Loss Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	0
U.S. Federal and Non-U.S. Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	493
U.S. Federal and Non-U.S. Jurisdiction [Member] | Two Thousand Fifteen Through Two Thousand Twenty Four [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	28
U.S. Federal and Non-U.S. Jurisdiction [Member] | Two Thousand Twenty Five Through Two Thousand Thirty Four [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	3
U.S. Federal and Non-U.S. Jurisdiction [Member] | Indefinite Life [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 462